Neutrophil Gelatinase-Associated Lipocalin in Peritoneal Dialysis-Related Peritonitis: Correlation with White Blood Cells over Time and a Possible Role as the Outcome Predictor

INTRODUCTION

The present study aimed to monitor peritoneal neutrophil gelatinase-associated lipocalin (pNGAL) during peritonitis episodes and to enhance its diagnostic value by evaluating pNGAL at scheduled times in parallel with white blood cell (WBC) count. In addition, we investigated possible correlations between pNGAL and the etiology of peritonitis, evaluating it as a possible marker of the clinical outcome.

METHODS

Twenty-two patients with peritoneal dialysis (PD)-related peritonitis were enrolled. Peritonitis was divided into Gram-positive, Gram-negative, polymicrobial, and sterile. WBC count and neutrophil gelatinase-associated lipocalin (NGAL) in PD effluent were measured at different times (days 0, 1, 5, 10, 15, and/or 20 and 10 days after antibiotic therapy discontinuation). NGAL was measured by standard quantitative laboratory-based immunoassay and by colorimetric NGAL dipstick (NGALds) (dipstick test).

RESULTS

We found strong correlations between peritoneal WBC, laboratory-based NGAL, and NGALds values, both overall and separated at each time point. On day 1, we observed no significant difference in WBC, both NGALds (p = 0.3, 0.9, and 0.2) between Gram-positive, Gram-negative, polymicrobial, and sterile peritonitis. No significant difference has been found between de novo versus relapsing peritonitis for all markers (p > 0.05). We observed a parallel decrease of WBC and both NGAL in patients with favorable outcomes. WBC count and both pNGAL resulted higher in patients with negative outcomes (defined as relapsing peritonitis, peritonitis-associated catheter removal, peritonitis-associated hemodialysis transfer, peritonitis-associated death) at day 10 (p = 0.04, p = 0.03, and p = 0.05, respectively) and day 15 (p = 0.01, p = 0.04, and tendency for p = 0.005). There was a tendency toward higher levels of WBC and NGAL in patients with a negative outcome at day 5. No significant difference in all parameters was proven at day 1 (p = 0.3, p = 0.9, p = 0.2) between groups.

CONCLUSION

This study confirms pNGAL as a valid and reliable biomarker for the diagnosis of PD-peritonitis and its monitoring. Its trend is parallel to WBC count during peritonitis episodes, in particular, patients with unfavorable outcomes.

Analysis of annual distributions of hemoglobin A2 values as a method to test for HbA2 standardization

BACKGROUND AND AIMS

The monitoring of yearly distributions of HbA2 measured has been indicated as a reliable indicator of worldwide standardization.

MATERIALS AND METHODS

Measurements/year of HbA2 have been collected over three consecutive years in 15 Italian laboratories each using the same analytical method over three years period. HbA2 distributions, cleaned of replicated measurements, were compared by the overlapping area of the raw probability density functions expressed by coefficient eta (η), and by comparing the reference intervals for the central part of each distribution estimated by the indirect method refineR using the R package "refineR".

RESULTS

According to the overlapping areas analysis the distributions/year of the data provided by 4 centers able to perform at least 1000 measurements/year were similar in 2 consecutive years. Moreover, the reference intervals provided by 2 centers using the same analytical methods in two separate locations over the three consecutive years, were very similar. The highest overlap (99.7 %) was observed in one center over two consecutive years. The overlapping areas were very high (93.6-95.7%) in 8 out of 9 inter-comparisons.

CONCLUSION

Despite the limitations of this study the yearly distribution of the HbA2 measured in various centers appears a reliable tool to test HbA2 standardization over different centers using different analytical methods.

Rheumatoid factor isotypes in rheumatoid arthritis diagnosis and prognosis: a systematic review and meta-analysis

OBJECTIVE

The first biomarker associated with the rheumatoid arthritis is rheumatoid factor (RF) and since the earliest reports a role has been proposed in the diagnosis and in the prediction of clinical features and outcome. The study of RF isotypes has further attempted to improve diagnostic accuracy and identify specific subgroups of patients. The main objective of this study is to provide an analysis of the literature on the role of RF isotypes in the diagnosis and prognosis of rheumatoid arthritis (RA).

METHODS

We performed a systematic literature review and meta-analysis on the role of RF isotypes in RA (only in English, from PubMed, search terms: "rheumatoid factor isotypes", "diagnosis", "prognosis" and "rheumatoid arthritis", last search 31 July 2022, two independent assessment of quality and biases, results included in tables and in the meta-analysis).

RESULTS

Thirty-six articles were examined (7517 patients). Testing all RF isotypes with latex test or nephelometry allows for the highest sensitivity (68.6%, 95% CI 66.2% to 71.0%); nonetheless, the determination of IgA isotype provides the highest specificity (91.4%, 95% CI 90.8% to 92.0%) and the highest positive likelihood ratio (7.7, 95% CI 5.7 to 10.4). When testing IgM isotype the highest diagnostic OR (21.7, 95% CI 16.1 to 29.3) is reached. When analysing anti-citrullinated protein antibodies, RF isotype determination increases diagnostic accuracy. On the other hand, these do not provide relevant prognostic information, as results are conflicting.

CONCLUSIONS

Testing RF allows the highest sensitivity, while IgA isotype the highest specificity and positive likelihood ratio for RA diagnosis. On the other hand, determination of RF isotypes dose not allow prognostic information, as data are limited and heterogeneous.

Relationship between Residual Urine Output and Type of Dialysis with FGF23 Levels

Several studies investigated the role of fibroblast growth factor 23 (FGF23) in the regulation of renal phosphate excretion in chronic kidney disease (CKD). However, patients with residual urine output (UO) seem to control their serum phosphorus levels better. Our aim was to determine whether FGF23 levels are influenced by dialysis modality and UO. We performed a cross-sectional study in hemodialysis (HD) and peritoneal dialysis (PD) patients. The C-terminal FGF23 (cFGF23) levels were determined in plasma with a two-site enzyme-linked immunosorbent assay. The UO collection referred to an mL/day measurement. All p values were two-sided, and the statistical significance was set at p < 0.05. We enrolled 133 patients (58 HD, 75 PD, UO 70%). The median cFGF23 was significantly higher in HD vs. PD patients (p = 0.0017) and not significantly higher in patients without UO (p = 0.12). We found a negative correlation between cFGF23 and the UO volume (p = 0.0250), but the correlation was not significant when considering the type of dialysis treatment. Phosphorus (ß = 0.21677; p = 0.0007), type of dialysis (ß = −0.68392; p = 0.0003), and creatinine (ß = 0.08130; p = 0.0133) were significant and independent predictors of cFGF23 levels. In conclusion, cFGF23 was significantly higher in HD than in PD patients. We found a significant negative correlation between cFGF23 and the residual UO volume, but the correlation was not significant considering the type of dialysis. Our study reveals that dialysis modality is an independent predictor of FGF23 levels. In particular, PD is associated with lower FGF23 levels than HD.

Evaluating the role of a fully automated SARS-CoV-2 antigen ECLIA immunoassay in the management of the SARS COV 2 pandemic on general population

OBJECTIVES

Chemiluminescence immunoassay (CLIA) automated assays (fourth-generation antigen test) for SARS-CoV-2 detection are promising because of their analytical productivity, but have lower sensitivity and specificity than rt-PCR assays. The authors of this paper evaluated a recent immunoassay implemented on Siemens Atellica IM, investigating how much this could affect the actual feasibility of this diagnostic during the pandemic.

METHODS

From the three-day routine 134 positive and 241 negative swab samples by rt-PCR test were evaluated, selected as 1/3 positive - 2/3 negative.

RESULTS

Using rt-PCR as gold standard, the specificity of immunoassay was 96.7%, while sensitivity was 68.0%. Sensitivity is inversely proportional to the viral load: 100% for cycles threshold (CT) values from 14 to 29, 95% until 30 CT, then 85, 74, 72, 68%, for 31-35 CT respectively.

CONCLUSIONS

Our study confirms the reliability of the fourth-generation antigen assay in recognizing negative samples. Conversely, sensitivity appears to be less reliable (68.0%) than reported in the literature. This could be due to a non-randomized study group: many swab samples were taken from patients with expected low viral load (hospitalized for COVID for more than 10-12 days or asymptomatic patients for epidemiological surveillance). The strong correlation of sensitivity and viral load could prove significant to track the infectiousness of infected people, as previous studies reported that a viral load of at least 10E6 copies of RNA/mL, corresponding to 25 CT, is the threshold of transmission of the disease.

Subclinical AKI and Clinical Outcomes in Elderly Patients Undergoing Cardiac Surgery: Diagnostic Utility of NGAL versus Standard Creatinine Increase Criteria

BACKGROUND

Acute kidney injury (AKI) is a common and serious postoperative complication in patients undergoing cardiac surgery and its incidence is particularly high among elderly patients. Cardiac surgery-associated AKI (CSA-AKI) represents the second most common cause of AKI in the intensive care unit but its true incidence could be underestimated, especially in elderly population. The current biomarkers of AKI are unreliable and delayed during acute changes in kidney function. In the setting of subclinical AKI (SAKI), biomarkers of tubular damage, such as NGAL, seem to be an early indicator of kidney damage. The aim of this study was to investigate NGAL utility in the SAKI diagnosis in the first 48 h after cardiac surgery and its helpfulness in predicting adverse clinical outcomes in comparison to current criteria for AKI.

METHODS

This is an observational study of 72 patients admitted to San Bortolo's cardiac surgery department for elective cardiosurgical procedure enrolled over a 5-months period. All patients underwent peripheral venous sample 48 h after cardiac surgery to assess plasmatic creatinine (48Cr) and NGAL (48pNGAL) in addition to exams already foreseen by clinical practice. For each patient we studied renal, respiratory and cardiovascular outcome during hospitalization as well as 30 days and 6 months mortality. Creatinine Increase AKI (CrIAKI) was defined by 48CrI ≥0.3 mg/dL and SAKI was defined by 48pNGAL ≥100 pg/dL. We also assessed Respiratory (ArespO) as well as Cardiovascular (ACvO) outcome.

RESULTS

Thirty days mortality was 8.3% (6 patients) and 6 months mortality was 12.5% (9 patients). A total of 27 patients (37.5%) presented AKI according to KDIGO (4) and 4 (5.5%) needed renal replacement therapy (RRT). SAKI was significantly associated with 30 days mortality (p = 0.0238), 6 months mortality (p = 0.002), Adverse renal outcome (ARenO) (p = 0.004) and need for RRT (p = 0.005). CrIAKI was significantly associated with 30 days mortality (p = 0.009) and ARenO (p = 0.0001), but not with 6 months mortality nor need for RRT.

Effects of preoperative high-oral protein loading on short- and long-term renal outcomes following cardiac surgery: a cohort study

BACKGROUND

Post-cardiac surgery acute kidney injury (AKI) is associated with increased mortality. A high-protein meal enhances the renal blood flow and glomerular filtration rate (GFR) and might protect the kidneys from acute ischemic insults. Hence, we assessed the effect of a preoperative high-oral protein load on post-cardiac surgery renal function and used experimental models to elucidate mechanisms by which protein might stimulate kidney-protective effects.

METHODS

The prospective "Preoperative Renal Functional Reserve Predicts Risk of AKI after Cardiac Operation" study follow-up was extended to postoperative 12 months for 109 patients. A 1:2 ratio propensity score matching method was used to identify a control group (n = 214) to comparatively evaluate the effects of a preoperative protein load and standard care. The primary endpoints were AKI development and postoperative estimated GFR (eGFR) loss at 3 and 12 months. We also assessed the secretion of tissue inhibitor of metalloproteases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7), biomarkers implicated in mediating kidney-protective mechanisms in human kidney tubular cells that we exposed to varying protein concentrations.

RESULTS

The AKI rate did not differ between the protein loading and control groups (13.6 vs. 12.3%; p = 0.5). However, the mean eGFR loss was lower in the former after 3 months (0.1 [95% CI - 1.4, - 1.7] vs. - 3.3 [95% CI - 4.4, - 2.2] ml/min/1.73 m²) and 12 months (- 2.7 [95% CI - 4.2, - 1.2] vs - 10.2 [95% CI - 11.3, - 9.1] ml/min/1.73 m²; p < 0.001 for both). On stratification based on AKI development, the eGFR loss after 12 months was also found to be lower in the former (- 8.0 [95% CI - 14.1, - 1.9] vs. - 18.6 [95% CI - 23.3, - 14.0] ml/min/1.73 m²; p = 0.008). A dose-response analysis of the protein treatment of the primary human proximal and distal tubule epithelial cells in culture showed significantly increased IGFBP7 and TIMP-2 expression.

CONCLUSIONS

A preoperative high-oral protein load did not reduce AKI development but was associated with greater renal function preservation in patients with and without AKI at 12 months post-cardiac surgery. The potential mechanisms of action by which protein loading may induce a kidney-protective response might include cell cycle inhibition of renal tubular epithelial cells. Clinical trial registration ClinicalTrials.gov: NCT03102541 (retrospectively registered on April 5, 2017) and ClinicalTrials.gov: NCT03092947 (retrospectively registered on March 28, 2017).

Clinical Assessment of Continuous Hemodialysis with the Medium Cutoff EMiC®2 Membrane in Patients with Septic Shock

INTRODUCTION

At the time of renal replacement therapy, approximately 20% of critically ill patients have septic shock. In this study, medium cutoff (MCO) continuous venovenous hemodialysis (CVVHD) was compared to high-flux membrane continuous venovenous hemodiafiltration (CVVHDF) in terms of hemodynamic improvement, efficiency, middle molecule removal, and inflammatory system activation.

METHODS

This is a monocenter crossover randomized study. Between December 31, 2017, and December 31, 2019, 20 patients with septic shock and stage 3 acute kidney injury (AKI) admitted to 2 Italian ICUs were enrolled. All patients underwent CVVHD with Ultraflux® EMiC®2 and CVVHDF with AV1000S® without washout. Each treatment lasted 24 h.

RESULTS

Compared to AV1000S®-CVVHDF, EMIC®2-CVVHD normalized cardiac index (β = -0.64; p = 0.02) and heart rate (β = 5.72; p = 0.01). Interleukin-8 and myeloperoxidase removal were greater with AV1000S®-CVVHDF than with EMiC®2-CVVHD (β = 0.35; p < 0.001; β = 0.43; p = 0.03, respectively). Leukocytosis improved over 24 h in EMiC®2-CVVHD-treated patients (β = 4.13; p = 0.03), whereas procalcitonin levels decreased regardless of the modality (β = 0.89; p = 0.01) over a 48-h treatment period. Reduction rates, instantaneous plasmatic clearance of urea, creatinine, and β2-microglobulin were similar across modalities. β2-Microglobulin removal efficacy was greater in the EMiC®2 group (β = 0-2.88; p = 0.002), while albumin levels did not differ. Albumin was undetectable in the effluent in both treatments.

DISCUSSION

In patients with septic shock and severe AKI, the efficacy of uremic toxin removal was comparable between MCO-CVVHD and CVVHDF. Further, MCO-CVVHD was associated with improved hemodynamics. Fraction of filtration and transmembrane pressure reduction and the maintenance of equal efficacy might be the key features of CVVHD with MCO membranes in critically ill patients.

Comparison of Anti-SARS-CoV-2 S1 Receptor-Binding Domain Antibody Immunoassays in Health Care Workers Before and After the BNT162b2 mRNA Vaccine

OBJECTIVES

The Pfizer-BioNTech BNT162b2 vaccine against SARS-CoV-2 infection is now available. This vaccine induces antibody production against the receptor-binding domain (RBD) of the spike glycoprotein S1 (S1-RBD). This study evaluated the performance of new immunoassays to measure this type of antibody.

METHODS

Blood samples were collected at t0 (prime dose), after 21 days (t1, booster dose), and then after another 15 days (t2) from 70 health care professionals who had tested negative for previous SARS-CoV-2 infection and underwent vaccination with BNT162b2.

RESULTS

Antibodies against S1-RBD were measured using 4 commercial assays. At t0, t1, and t2, the median antibody concentrations (interquartile range) were, respectively, 0.2 (0.1-0.4), 49.5 (19.1-95.7), and 888.0 (603.6-1,345.8) U/mL by Maglumi SARS-CoV-2 S-RBD immunoglobulin G (IgG) (Shenzen New Industries Biomedical Engineering, Snibe Diagnostics); 0.0 (0.0-0.0), 7.9 (4.2-15.6), and 112.3 (76.4-205.6) U/mL by Atellica IM SARS-CoV-2 IgG assay (Siemens Healthineers); 0.0 (0.0-0.0), 59.9 (18.3-122.0), and 2,646.0 (1,351.2-4,124.0) U/mL by Elecsys Anti-SARS-CoV-2 S assay (Roche Diagnostics); and 1.8 (1.8-1.8), 184 (94-294), and 1,841.0 (1,080.0-2,900.0) AU/mL by LIAISON SARS-CoV-2 TrimericS IgG assay (DiaSorin). The differences between medians at t0, t1, and t2 were all statistically significant (P < .001).

CONCLUSIONS

Antibodies against nucleocapsid proteins (N) were also measured using Maglumi 2019-nCoV IgG assay, which showed all negative results. All the considered anti-RBD methods detected response to the vaccine, while the method directed against anti-N failed to show response.

Improvements and limits of anti SARS-CoV-2 antibodies assays by WHO (NIBSC 20/136) standardization

OBJECTIVES

A few CLIA automated immunoassays for the recognition of anti S1-RBD SARS-CoV-2 antibodies have recently been placed on the market. Preliminary data demonstrate a high correlation between methods but wide differences in absolute concentrations. A new WHO international standard for anti-SARS-CoV-2 immunoglobulin, NIBSC code 20/136, has been recently introduced to reduce the differences. The aim of this study is thus to verify the harmonization made by NIBSC 20/136 on Ab anti S1-RBD measurement on real samples.

METHODS

The following assays were studied: LIAISON^® SARS-CoV-2 TrimericS IgG (DiaSorin); Elecsys^® anti-SARS-CoV-2 S (ROCHE); Atellica IM SARS-CoV-2 IgG (sCOVG) (Siemens); MAGLUMI^® SARS-CoV-2 S-RBD IgG (Snibe), measuring 210 samples from 70 health workers with no previous SARS-CoV2 infection, during their Pfizer-BioNTech's BNT162b2 vaccination period.

RESULTS

The recalculation of concentrations based on the NIBSC 20/136 standardization improve the analytical and diagnostic comparability but do not cancel this variability between methods: recalibrated results remain different across methods, both in terms of tendency and single data.

CONCLUSIONS

The recalculation of concentrations based on the NIBSC 20/136 standardization improves the analytical and diagnostic comparability but does not cancel the differences between methods: recalibrated results remain different across methods, both in terms of tendency and single data.

Clinical Implications of the New Equation to Estimate Glomerular Filtration Rate

Recently, a new full-age spectrum equation was proposed by the European Kidney Function Consortium (EKFC) to overcome the difficulty of using multiple glomerular filtration rate (GFR) estimation equations and problems of implausible changes in GFR during the transition from adolescence to adulthood and address GFR overestimation in young adults and in the older adults. To verify the impact on patient classifications, we applied the new equation to data of 38,188 adult patients, comparing GFR estimation using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and EKFC equations. As expected, our data indicate that a significant proportion of patients will be reclassified downward by the EKFC compared to the CKD-EPI equation with a particular reference between CKD stages 1-2 and 2-3 and age categories of 18-30 and ≥61 years, respectively. Clinicians should be aware that any replacement for the EKFC equation will entail a period of different results in estimated GFR during the transition from the previous to the new equation.

MO063DESCRIPTION OF GENETIC VARIANTS IN A COHORT OF TOLVAPTAN ADPKD PATIENTS

Background and Aims

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common inherited renal cystic disease. It is genetically heterogeneous: 72-75% of ADPKD cases are related to mutations in the PKD1, 15-18 % to PKD2 and the remaining 7–10% of affected are genetically unresolved (GUR). Recent years, new drugs have emerged as promising agents that may retard the progression of ADPKD, such as Tolvaptan. In Italy Tolvaptan is available since 2016 and commonly used since 2017 in ADPKD patients, which fulfill the criteria of “rapid disease progression”, according to the European recommendations. High intra-interfamilial variability in pedigrees was observed, despite the same germ-line mutation. This could be explained by other clinical or genetic factors (environmental, modifier genes, etc), that may affect disease severity. The aim of the study is to describe the genetic variants in a cohort of Tolvaptan ADPKD patients (pts) referral to Renal Genetic Disease Ambulatory of Nephrology Department.

Method

Patients with ADPKD and in Tolvaptan treatment were enrolled. Diagnosis of ADPKD was made upon the revised Ravine’s criteria and Eligibility Criteria for Tolvaptan was made upon Italian indication for Tolvaptan prescription according to Italian Medicine Agency (AIFA) and European Medicines Agency (EMA). We performed genetic analysis (PKD1, PKD2 and PKHD1 genes) to identify mutations by NGS capture-based target enrichment kit (Sophia Genetic™), sequencing on Illumina MySeq Platform® and Sanger Sequencing on 3500 Series Genetic Analyzer (Applied Biosystems™).

Results

Eighteen pts [median age 46 (IQR 39-48) yrs ], 12 male, were included in the analysis. We manage to perform genetic analysis in all pts. Genetic analysis was essential in 4 patients without family history for Tolvaptan eligibility. Sixteen pts (88,9%) have mutations in PKD1, confirming what is already known from the literature for rapid progressor subjects; 2 pts are characterized by PKD2 mutations, both truncating. In only one pt, concomitant with a PKD1 mutation, also a PKHD1 mutation was found. In order to better characterize the cohort it was decided to subdivide the pts into 3 groups, by gene involvement and mutation type:

1st group: 12 Subjects with truncated PKD1 mutation (66.7%). In 7 pts (58,3%) the mutations are within exons (5 and from exon 11 to 15 inclusive) that encode for Immunoglobulin-like repeats or PKD domain of Polycystin 1 (PC1).

2nd group: 4 Subjects with non-truncated PKD1 mutations (22.2%). 3 pts (75.0%) are characterized by missense variants, as previous studies highlighted (a higher percentage of missense mutations in subjects with non-truncating mutations). In 2 pts (50%) the mutations are within exons (2 and 6) that encode for C-type lectin domain (CTLs) di PC1 and typical domain of extracellular protein.

3rd group: 2 Subjects with a PKD2 mutation (11.1%), both truncating. These data confirmed the lower mutation rate of PKD2 compared to PKD1 and highlighted an effective prevalence of truncation mutations in rapid disease progressors as previous reported.

Conclusion

Although our cohort of patients is small, we manage to perform genetic analysis in all pts reaching a detection rate of 100%. In 9 of 16 pts (56,3%) with PKD1 mutation the presence of mutations in exons coding PKD domain in PC1 or Immunoglobulin-like repeats or typical domain of extracellular protein allows us to hypothesize that the resulting alteration of the polycystin-mediated cell recognition and communication processes play a crucial role in the pathogenesis of ADPKD.

The impact of COVID-19 first wave on long term care facilities of an Italian Province: an historical reference

The coronavirus disease 2019 (COVID-19) pandemic will leave a profound imprint in the collective memory of humanity. In Italy, Long-Term Care Facilities (LTCFs) have seen a disproportionally high number of deaths during and the COVID-19 pandemic and, certainly, they may be considered as its epicenter. Aiming to leave a symbolic mark of what the pandemic did in these care settings, we report on an outbreak in a single LTCF where, 53 out of 64 residents, resulted infected. Our narration is based on an epidemiological field investigation together with a calendar of passages through the stages of disease in the infected population. We found an age-gradient in all clinical and epidemiological variables explored such as symptoms onset, illness severity, recovery from symptoms and deaths. According to the disease staging, 26 (49%) were asymptomatic; 9 (17%) had a mild disease; 7 (13%) a moderate stage and 11 (21%) a severe illness severity of whom 10 died. For a more comprehensive description of the impact of the pandemic on LTCFs, we compared the standard mortality ratio (SMR) in the first six months of 2020 to that of 2018 and 2019 in all the 34 facilities of the Vicenza province. Overall, there was a SMR higher 60% than the equivalent period of the previous years.

Gadolinium-based contrast media exposure and the possible risk of subclinical kidney damage: a pilot study

PURPOSE

We performed a pilot study to evaluate the feasibility of future research about the presence of subclinical kidney damage after Gadolinium-based contrast media exposure. The future study aims to understand which are the behaviors of two markers of kidney damage, such as urinary NephroCheck (NC) and/or neutrophil gelatinase-associated lipocalin (NGAL). Specifically, after GBCM exposure, NC urinary detection should identify proximal tubule damage while NGAL urinary detection should be related to distal tubule damage.

METHODS

We performed a pilot study in patients who had Gadolinium exposure. The feasibility of future study is reached when at least 90% of candidates completed the pilot study. In each patient, we tested urinary NC and NGAL levels 24 h before magnetic resonance imaging (MRI) and 12-24 h after the exposure. Furthermore, we evaluated the administration of other nephrotoxic agents, the presence of comorbidity, and kidney function by S-creatinine and urine protein before the MRI.

RESULTS

We enrolled 35 candidates of whom 33 patients completed all study procedures. Our population had a mean age of 60.7 ± 14.8 years with normal kidney function with a median S-creatinine equal to 0.7 mg/dl (Interquartile range [IQR] 0.6-0.91). Urinary NC levels increased from 0.21 ng²/ml² (IQR 0.11-0.4) before MRI to 0.34 ng²/ml² (IQR 0.16-0.86) (p = 0.005). Conversely, we did not appreciate any significant modification in urinary NGAL (p = 0.53).

CONCLUSION

Our pilot study seems adequate in terms of feasibility and encourages us to focus our future research on renal proximal tubule, as the principal site of subclinical kidney damage after Gadolinium exposure.

Anti SARS-CoV-2 antibodies monitoring in a group of residents in a long term care facility during COVID-19 pandemic peak

Objectives Clinical laboratories plays a key role in screening, diagnosis and containment of the Coronavirus 2019 infection epidemic. The etiological diagnosis presupposes the isolation of virus genetic material in the patient's biological sample but laboratory diagnostics also make use of searching possibility for immunoglobulin (Ig)G, IgM classes antibodies. The characteristics of the antibody response are not yet completely clear. Methods This study describes a serological monitoring of subjects, elderly nursing care residence guests, interested by a very large infection outbreak. After first nasopharyngeal swab, all the positive subjects (43) were monitored for the persistence of the virus infection through nasopharyngeal swab after 20 days (16-24), 32 days (28-36) and after 49 days (47-50). At the same time, during the second (day 32) and third (day 49) follow up, all the guests were investigated for IgM and IgG anti SARS-CoV-2 antibodies, by using a quantitative chemiluminescence method. Results Thirty two days after performing the first diagnostic swab, 39 of 43 patients (90%) had IgG higher than the cut off value. After 49 days the four patients with negative IgG were still negative. The comparison of the levels of IgG-Ab between the controls shows a significant decrease in concentrations (-10%). Conclusions Our study confirms that in most patients affected by COVID-19 there is a typical antibody response with IgG-Ab present in 90% of nursing care COVID-19 positive residence guests. For IgM-Ab only 23% of tested subjects were positive on the 32nd and 49th day of illness, always in parallel with the IgG-Ab positivity.

Evaluation of STA-NeoPTimal, an extraction thromboplastin reagent with ISI close to 1

INTRODUCTION

The prothrombin time (PT) is the most requested test to investigate patients with congenital or acquired coagulopathies or to monitor oral anticoagulant therapy. However, thromboplastins can show markedly different responsiveness to the defects induced by vitamin K antagonist (VKA) therapy and are thus characterized by their ISI (International Sensitivity Index). INR results are optimal for patients under VKA but for patients screened for other reasons expressing PT results as ratio can be more appropriate. As it is very difficult to define the PT results reporting unit from the PT testing request, it would be ideal to use a thromboplastin with ISI = 1. The study aims to compare our reference PT reagent with two candidate thromboplastins with ISI close to 1.

METHODS

We compared 3 different thromplastins: two rabbit brain extracted based reagents (STA-Neoplastine CI Plus, with ISI = 1.26, routinely used in our laboratory and STA-NeoPTimal with ISI = 1.01) and a recombinant thromboplastin (STA-Neoplastine R with ISI = 0.97). The comparison was done on 175 samples: 75 from individuals without coagulation defects and 100 from patients under VKA.

RESULTS

STA-NeoPTimal and STA-Neoplastine R well correlate to our reference, STA-Neoplastine CI Plus: regression equations are y = 1.186x-0.1351, r²  = .9454 and y = 1.1432x-0.1554, r²  = .9951, respectively. The lowest bias on INR results was obtained with STA-NeoPTimal reagent (interval: -0.7/+0.4).

CONCLUSION

We conclude that STA-NeoPTimal can be used in the laboratory as it gives results comparable to those obtained with STA-Neoplastine CI Plus. Besides, thanks to its ISI = 1, it guarantees reporting a PT ratio equal to INR which avoids errors.

Influence of patients’ clinical features at intensive care unit admission on performance of cell cycle arrest biomarkers in predicting acute kidney injury

Objectives

Identification of acute kidney injury (AKI) can be challenging in patients with a variety of clinical features at intensive care unit (ICU) admission, and the capacity of biomarkers in this subpopulation has been poorly studied. In our study we examined the influence that patients’ clinical features at ICU admission have over the predicting ability of the combination of urinary tissue inhibitor of metalloproteinase-2 (TIMP2) and insulin-like growth factor binding protein 7 (IGFBP7).

Methods

Urinary [TIMP2]•[IGFBP7] were measured for all patients upon admission to ICU. We calculated the receiver operating characteristics (ROC) curves for AKI prediction in the overall cohort and for subgroups of patients according to etiology of ICU admission, which included: sepsis, trauma, neurological conditions, cardiovascular diseases, respiratory diseases, and non-classifiable causes.

Results

In the overall cohort of 719 patients, 239 (33.2%) developed AKI in the first seven days. [TIMP2]•[IGFBP7] at ICU admission were significantly higher in AKI patients than in non-AKI patients. This is true not only for the overall cohort but also in the other subgroups. The area under the ROC curve (AUC) for [TIMP2]•[IGFBP7] in predicting AKI in the first seven days was 0.633 (95% CI 0.588–0.678), for the overall cohort, with sensitivity and specificity of 66.1 and 51.9% respectively. When we considered patients with combined sepsis, trauma, and respiratory disease we found a higher AUC than patients without these conditions (0.711 vs. 0.575; p=0.002).

Conclusions

The accuracy of [TIMP2]•[IGFBP7] in predicting the risk of AKI in the first seven days after ICU admission has significant variability when the reason for ICU admission is considered.

P0727P-CRESYL SULFATE AND INDOXYL SULFATE: A POSSIBLE ROLE AS BIOMARKERS IN THE PREDICTION OF RENAL FUNCTION AND CKD PROGRESSION

Background and Aims

Uremic toxins are markedly accumulated in chronic kidney disease (CKD) patients. Among these two protein-bound compounds, indoxyl sulfate (IXS) and p-cresyl sulfate (PCS) derived from gut bacterial transformation, play an important role. Recent evidences demonstrate their toxic effects in vitro and may contribute in vivo to CKD progression and mortality in uremic patients. For this reason, bacterial metabolism and its metabolites are therapeutic targets in CKD. While, several studies have evaluated possible associations between these two compounds and renal function decline in CKD, while no study has evaluated them according to the stage of progression (CKD stage). In this study, PCS and IXS are considered to highlight the possible role as biomarkers in the prediction of renal function and CKD progression (GFR stage 1-5).

Method

In our observational, prospective study we evaluated total (t) and free (f) PCS and IXS plasmatic fractions using Ultra High Performance Liquid Chromatography Infinity 1260 (Agilent technologies) coupled to an API 3200™ triple quadrupole mass spectrometry (ABSciex). Data were shown as mean ± SD or median (25th-75th). Statistical analysis was done by SPSS version 24.0

Results

We evaluated 80 CKD patients: 54.68 ± 12.88 yrs, 39 F and 41 M. The median creatinine was 1.58 (0.90-3.32) mg/dL, median urea 58.50 (42.0-121.25) mg/dL and eGFR (CKD-EPI) 42 (17.25-85.75) mL/min/1.73 m2. On the table 1, it was summarized the levels of PCS and IXS in all patients and classified by GFR (G) stages. We found the statistically significant increase of total and free fractions of PCS (p&lt;0.001) and IXS (p&lt;0.001) with the progression of CKD by G stage and inverse strong correlation between eGFR (CKD-EPI) and PCSt (Spearman's Rho (r)=-0.70, p&lt;0.001), PCSf (r=-0.75, p&lt;0.001), IXSt (r=-0.76, p&lt;0.001), IXSf (r=-0.82, p&lt;0.001).

Moreover, the increase of PCS and IXS predicts the eGFR decline significantly, according to the linear regression model using eGFR as dependent variable: PCSt (R-squared (R2)= 0.34, p&lt;0.001). PCSf (R2=0.21, p&lt;0.001). IXSt (R2=0.27, p&lt;0.001). IXSf (R2=0.19, p&lt;0.001). By multivariate analysis, the total compounds of both toxins remain predictive of eGFR: PCSt (β=-0.72, p=0.003; 95%CI:-2.43;-0.54) and IXSt (β=-0.70, p=0.011; 95%CI:-5.15;-0.70).

Conclusion

In conclusion, in our study we show the strong correlations between and PCS and IXS and eGFR and we found the significantly increase of PCS and IXS (total and free) with the progression of CKD in all G stage (1-5). We highlight the use of mass spectrometry in the evaluation of renal function especially in the earliest stages of CKD with the possibility of measuring minimum concentrations of PCSf and IXSf.

Assuming the predictive value of PCS and IXS towards the reduction of eGFR, we could hypothesize the identification of cut-offs based on confidence intervals, for the prediction and progression of renal function impairment.

Urinary [TIMP-2] × [IGFBP7] and serum procalcitonin to predict and assess the risk for short-term outcomes in septic and non-septic critically ill patients

BACKGROUND

Biomarkers can play a critical role by facilitating diagnosis and stratification of disease, as well as assessment or prediction of disease severity. Urinary tissue inhibitor of metalloproteinase-2 and insulin-like growth factor binding protein 7 product ([TIMP-2] × [IGFBP7]) predict the development and progression of AKI and recently procalcitonin (PCT), a widely used biomarker for sepsis diagnosis and management, has been associated with AKI occurrence in ICU patients. To assess combinations of [TIMP-2] × [IGFBP7] and PCT results for prediction and risk stratification of short-term outcomes in septic and non-septic patients, a retrospective cohort analysis of critically ill patients was performed in a multidisciplinary ICU. ROC curve analysis was used in order to evaluate predictive performance of combined results of [TIMP-2] × [IGFBP7] and PCT at the time of admission for AKI development. To verify the utility of adding [TIMP-2] × [IGFBP7] and PCT results for risk assessment, we evaluated the predictive value of having a single-marker positivity compared to a double-marker positivity using the widely used cut-off of 0.3 (ng/mL)²/1000 for [TIMP-2] × [IGFBP7] and 0.5 μg/L for PCT. Risk assessment for AKI occurrence within 48 h, acute kidney disease (AKD) and mortality at 7 days was performed by logistic/Cox regression analysis.

RESULTS

433 patients were analysed, of whom 168 had AKI within 48 h (93 septic and 65 non-septic patients). Combination of [TIMP-2] × [IGFBP7] and PCT showed a good predictive ability for AKI occurrence (AUC 0.81, 95% CI 0.77-0.86, p < 0.001, Sens 78%, Spec 73%). Combinations of biomarkers increased the odd ratios (OR) considerably. A single-marker positivity showed a fourfold risk increase, while the double-marker positivity a 26-fold risk increase for AKI occurrence. Moreover, the double-marker positivity showed an elevated risk for AKD at 7 days in non-septic patients (OR 15.9, 95% CI 3,21-73,57, p < 0.001) and for mortality within 7 days in septic patients (HR 4.1, 95% CI 1.4-11.8, p = 0.001).

CONCLUSIONS

Although combining the results of [TIMP-2] × [IGFBP7] and PCT may be a useful tool to identify and stratify ICU patients at high risk for septic AKI and short-term adverse outcomes, data should be confirmed in a large prospective study.

Subclinical Contrast-Induced Acute Kidney Injury in Patients Undergoing Cerebral Computed Tomography

INTRODUCTION

The nephrotoxicity of modern contrast media remains controversial. Novel biomarkers of kidney damage may help in identifying a subclinical structural renal injury not revealed by widely used markers of kidney function.

OBJECTIVE

The aim of this study was to investigate clinical (contrast-induced acute kidney injury [CI-AKI]) and subclinical CI-AKI (SCI-AKI) after intra-arterial administration of Iodixanol and Iopamidol in patients with an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2.

METHODS

This is a prospective observational monocentric study. Urinary sample was collected at 4-8 h after contrast medium exposure to measure neutrophil gelatinase associated lipocalin (NGAL) and the product tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 ([TIMP-2] × [IGFBP7]), while blood samples were collected at 24 and 48 h after exposure to measure serum creatinine.

RESULTS

One hundred patients were enrolled, of whom 53 were exposed to Iodixanol and 47 to Iopamidol. Patients in Iodixanol and Iopamidol groups were comparable in terms of demographics, pre-procedural and procedural data. No patient developed CI-AKI according KDIGO criteria, while 13 patients reported SCI-AKI after exposure to iodine-based medium contrast (3 patients in Iodixanol group and 10 patients in Iopamidol group), defined by positive results of NGAL and/or [TIMP-2] × [IGFBP7]. A positive correlation was found between NGAL and [TIMP-2] × [IGFBP7] in the analysed population (Spearman's rho 0.49, p < 0.001). In logistic regression analysis, Iopamidol exposure showed higher risk for SCI-AKI compared to Iodixanol (OR 4.5 [95% CI 1.16-17.52], p = 0.030), even after controlling for eGFR and volume of contrast medium used.

CONCLUSIONS

This study showed that intra-arterial modern contrast media administration may have a nephrotoxic effect in a population without pre-existing chronic kidney disease. Further investigations on larger scale are warranted to confirm if Iopamidol exposed patients to increased risk of SCI-AKI compared to Iodixanol.

Acute rejection in kidney transplantation and the evaluation of associated polymorphisms (SNPs): the importance of sample size

Background Acute rejection (AR) is one of the most frequent complications after kidney transplantation (KT). Scientific evidence reports that some single-nucleotide polymorphisms (SNPs) located in genes involved in the immune response and in the pharmacokinetics and pharmacodynamics of immunosuppressive drugs are associated with rejection in renal transplant patients. The aim of this study was to evaluate some SNPs located in six genes: interleukin-10 (IL-10), tumor necrosis factor (TNF), adenosine triphosphate-binding cassette sub-family B member 1 (ABCB1), uridine diphosphate glucuronosyltransferase family 1 member A9 (UGT1A9), inosine monophosphate dehydrogenase 1 (IMPDH1) and IMPDH2. Methods We enrolled cases with at least one AR after KT and two groups of controls: patients without any AR after KT and healthy blood donors. Genetic analysis on DNA was performed. The heterozygosity (HET) was determined and the Hardy-Weinberg equilibrium (HWE) test was performed for each SNP. The sample size was calculated using the QUANTO program and the genetic associations were calculated using the SAS program (SAS Institute Inc., Cary, NC, USA). Results In our previous preliminary study (sample size was not reached for cases), the results showed that patients with the C allele in the SNP rs1045642 and the A allele in the SNP rs2032582 of the ABCB1 gene had more frequent AR. In contrast, with the achievement of sample size, the trend of the previous data was not confirmed. Conclusions Our study highlights a fundamental aspect of scientific research that is generally presumed, i.e. the sample size of groups enrolled for a scientific study. We believe that our study will make a significant contribution to the scientific community in the discussion of the importance of the analysis and the achievement of sample size to evaluate the associations between SNPs and the studied event.

Current understanding and future directions in the application of TIMP-2 and IGFBP7 in AKI clinical practice

NephroCheck® is the commercial name of a combined product of two urinary biomarkers, tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7), expressed as [TIMP-2]·[IGFBP7], used to identify patients at high risk of acute kidney injury (AKI). AKI is a common and harmful complication especially in critically-ill patients, which can induce devastating short- and long-term outcomes. Over the past decade, numerous clinical studies have evaluated the utility of several biomarkers (e.g. neutrophil gelatinase-associated lipocalin, interleukin-18, liver-type fatty acid binding protein and kidney injury molecule-1, cystatin C) in the early diagnosis and risk stratification of AKI. Among all these biomarkers, [TIMP-2]·[IGFBP7] was confirmed to be superior in early detection of AKI, before the decrease of renal function is evident. In 2014, the US Food and Drug Administration permitted marketing of NephroCheck® (Astute Medical) (measuring urinary [TIMP-2]·[IGFBP7]) to determine if certain critically-ill patients are at risk of developing moderate to severe AKI. It has since been applied to clinical work in many hospitals of the United States and Europe to improve the diagnostic accuracy and outcomes of AKI patients. Now, more and more research is devoted to the evaluation of its application value, meaning and method in different clinical settings. In this review, we summarize the current research status of [TIMP-2]·[IGFBP7] and point out its future directions.

Routine Adoption of Urinary [IGFBP7]∙[TIMP-2] to Assess Acute Kidney Injury at Any Stage 12 hours After Intensive Care Unit Admission: a Prospective Cohort Study

The urinary tissue inhibitor of metalloproteinases-2 and insulin-like growth factor-binding protein 7 ([TIMP-2]∙[IGFBP7]) have been introduced to improve risk prediction of severe acute kidney injury (AKI) within 12 hours of measurement. We performed a prospective cohort study to evaluate if the predictive value of [TIMP-2]∙[IGFBP7] for AKI might continue after 12 hours. We enrolled 442 critically ill adult patients from June to December 2016. Urine samples were collected at admission for [TIMP-2]∙[IGFBP7] measurement. Baseline patient characteristics were recorded including patients' demographics, prior health history, and the main reason for admission to build a logistic regression model to predict AKI. AKI occurrence differed between patients with [TIMP-2]∙[IGFBP7] ≤0.3 and >0.3 (ng/ml)2/1000 (31.9% and 68.10% respectively; p < 0.001). Patients with AKI had higher biomarker values compared to those without AKI (0.66 (0.21-2.84) vs 0.22 (0.08-0.63) (ng/ml)2/1000; p < 0.001). [TIMP-2]∙[IGFBP7] at ICU admission had a lower performance in predicting AKI at any stage within 48 hours and 7 days after measurement (area under the receiver operating characteristic curve (AUC) equal to 0.70 (95%CI 0.65-0.76), AUC 0.68 (95%CI 0.63-0.73)). In the logistic regression model, 0.1 (ng/ml)2/1000-unit increment was likely to increase the risk of AKI by 2% (p = 0.002).

Clinical impact of citrate-containing tubes on the detection of glucose abnormalities by the oral glucose tolerance test

Background

Plasma glucose levels provide the cornerstone of diabetes evaluation, and so it is crucial that clinical laboratories provide accurate and reliable plasma glucose results. To prevent in vitro glycolysis, citrate is used. Here, we present the first study on the 75-g oral glucose tolerance test (OGTT) using the currently available new citrate-containing tubes in liquid and granular forms and the previous sodium fluoride (NaF) for the diagnosis of carbohydrate metabolism disorders and gestational diabetes mellitus (GDM) according to the American Diabetes Association (ADA) guidelines.

Methods

The 75-g OGTT was performed in 147 volunteers, 83 of whom were pregnant women. Blood was collected in NaF/K3 ethylenediaminetetraacetic acid (EDTA) and NaF/Na2EDTA/citrate in liquid form in tubes in Brescia and in NaF/K2Ox and NaF/Na2EDTA/citrate in granular form in Vicenza. Glucose was measured within 3–4 h from the OGTT. The mean biases were calculated and compared with the desirable bias (<± 2.1%).

Results

OGTT glucose concentrations were higher in citrate tubes when compared to NaF-containing tubes. When citrate tubes were used, GDM increased to 12.5 and 11.7% in Brescia and Vicenza, respectively. Impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and diabetes mellitus (DM) increased to 36.7, 6.7 and 3.4%, respectively, in Brescia. In Vicenza, an increase of 47 and 1.9% in IFG and IGT, respectively, was found.

Conclusions

OGTT glucose measurement in citrate-containing tubes was shown to be more effective than those containing only NaF in diagnosing carbohydrate disorders. This new glycolysis inhibitor seems to be a necessary preanalytical tool for accurate and reliable plasma glucose results.

Tissue inhibitor metalloproteinase-2 (TIMP-2) • IGF-binding protein-7 (IGFBP7) levels are associated with adverse outcomes in patients in the intensive care unit with acute kidney injury

The G1 cell cycle inhibitors tissue inhibitor metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) have been identified as novel biomarkers for the prediction of moderate to severe acute kidney injury (AKI) risk. However, the prognostic value of [TIMP-2]•[IGFBP7] in predicting adverse outcomes in intensive care unit (ICU) patients with AKI was not previously described. To evaluate this, we conducted a cohort study, measuring [TIMP2]•[IGFBP7] levels in critically ill patients admitted to the ICU and classified the patients as NephroCheck (NC) (+) or NC (-) according to [TIMP-2]•[IGFBP7] values and AKI (+) or AKI (-) according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria. We then evaluated the incidence of continuous renal replacement therapy initiation, all-cause mortality and a composite endpoint of both in the four groups. Baseline [TIMP-2]•[IGFBP7] values were available for 719 patients, of whom 239 developed AKI and 151 met the composite endpoint. Compared to NC (-)/AKI (+) patients, NC (+)/AKI (+) patients had a significant risk of ICU mortality and the composite endpoint. Kaplan-Meier curves showed that the survival estimate for the composite endpoint of NC (+)/AKI (+) patients was 34.4%; significantly worse than NC (-)/AKI (+) patients (67.4%). Multivariate analyses showed strong association between NC positivity and the composite endpoint. The inflammatory marker, procalcitonin, was an additional prognostic biomarker to compare and confirm the incremental value of NephroCheck. No association between procalcitonin and the composite endpoint was found, especially in patients with AKI, suggesting that NephroCheck may be more kidney specific. Thus, the [TIMP-2]•[IGFBP7] values can serve to identify patients with AKI at increased risk for adverse outcomes in the ICU.

Analytical Assessment of the New Roche Cobas t 711 Fully Automated Coagulation Analyzer

This study aimed to provide a preliminary evaluation of the analytical performance of the new Roche cobas t 711 fully automated coagulation analyzer, which uses both liquid and lyophilized reagent cassettes. The analytical assessment included analysis of imprecision and linearity of prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen on cobas t 711 analyzer. Test results of 120 routine plasma samples were also compared with those obtained using two other coagulation analyzers (Instrumentation Laboratory ACL TOP 700 and Stago STA-R MAX). The accuracy, imprecision, and comparability of manual and automatic lyophilized material resuspension were also evaluated using 200 routine plasma samples. Overall, automatic resuspension was found to be more precise than, and equally accurate as, manual reconstitution, with coefficient of variations (CV%) three- to sixfold lower compared with manual reconstitution. The analytical imprecision was found to be excellent, as attested by total CV% of 0.7% for PT, 1.7 to 1.8% for APTT, and 1.9 to 3.2% for fibrinogen. Linearity was excellent over a clinically significant range of PT, APTT, and fibrinogen values, displaying correlation coefficients comprised between 0.994 and 0.999. Methods comparison studies revealed that results of PT, APTT, and fibrinogen on cobas t 711 are globally aligned with those obtained using identical plasma samples on IL ACL TOP 700 and Stago STA-R MAX, displaying correlation coefficients of 0.97 for PT, 0.81 and 0.88 for APTT, 0.90 and 0.94 for fibrinogen, respectively. In conclusion, the results of this preliminary evaluation demonstrate that PT, APTT, and fibrinogen on cobas t 711 coagulation analyzer displays excellent performance for routine use in clinical laboratories.

Presepsin and Procalcitonin Levels as Markers of Adverse Postoperative Complications and Mortality in Cardiac Surgery Patients

Backgound: This study was aimed at evaluating the presepsin and procalcitonin levels to predict adverse postoperative complications and mortality in cardiac surgery patients. Methods: A total of 122 cardiac surgery patients were enrolled for the study. Presepsin and procalcitonin levels were measured 48 h after the procedure. The primary endpoints were adverse renal, respiratory, and cardiovascular outcomes and mortality. Results: Presepsin and procalcitonin levels were significantly higher in patients with adverse renal and respiratory outcome (p < 0.001 and 0.0081). The presepsin levels were significantly higher in patients with adverse cardiovascular outcome (p = 0.023) and the procalcitonin values in patients with sepsis (p = 0.0013). Presepsin levels were significantly higher in patients who died during hospitalization (382 pg/mL, interquartile range [IQR] 243–717.5 vs. 1,848 pg/mL, IQR 998–5,451.5, p = 0.049). In addition, the predictive value for in-hospital, 30-days, and 6-months mortality was higher for presepsin, with a significant difference between the 2 biomarkers (p = 0.025, p = 0.035, p = 0.003; respectively). Presepsin and procalcitonin seem to have comparable predictive value for adverse renal, cardiovascular, and respiratory outcome in cardiac surgery patients. Although a positive trend was notable for presepsin and adverse renal outcome (area under the ROC [receiver operating characteristic] curves [AUC] of 0.760, 95% CI 0.673–0.833 versus procalcitonin: AUC 0.692; 95% CI 0.601–0.773): no statistically significant difference was evident between the AUC of the 2 biomarkers (p = 0.25). Conclusions: Presepsin and ­procalcitonin seem to have comparable predictive value for ­adverse renal, cardiovascular, and respiratory outcome in cardiac surgery patients. Also, presepsin possesses a better predictive value for in-hospital, 30-days, and 6-months mortality.

Cerebrospinal fluid analysis and the determination of oligoclonal bands

This document presents the guidelines for the cerebrospinal fluid (CSF) analysis and the determination of oligoclonal bands (OCBs) as pivotal tests in neuroinflammatory pathologies of the central nervous system. The guidelines have been developed following a consensus process built on questionnaire-based surveys, internet contacts, and discussions at workshops of the sponsoring Italian Association of Neuroimmunology (AINI) congresses. Essential clinical information on the pathologies in which the CSF analysis is indicated, and, particularly, on those characterized by the presence of OCBs in the intrathecal compartment, indications and limits of CSF analysis and OCB determination, instructions for result interpretation, and agreed laboratory protocols (Appendix) are reported for the communicative community of neurologists and clinical pathologists.

Preoperative Renal Functional Reserve Predicts Risk of Acute Kidney Injury After Cardiac Operation

BACKGROUND

Although acute kidney injury (AKI) frequently complicates cardiac operations, methods to determine AKI risk in patients without underlying kidney disease are lacking. Renal functional reserve (RFR) can be used to measure the capacity of the kidney to increase glomerular filtration rate under conditions of physiologic stress and may serve as a functional marker that assesses susceptibility to injury. We sought to determine whether preoperative RFR predicts postoperative AKI.

METHODS

We enrolled 110 patients with normal resting glomerular filtration rates undergoing elective cardiac operation. Preoperative RFR was measured by using a high oral protein load test. The primary end point was the ability of preoperative RFR to predict AKI within 7 days of operation. Secondary end points included the ability of a risk prediction model, including demographic and comorbidity covariates, RFR, and intraoperative variables to predict AKI, and the ability of postoperative cell cycle arrest markers at various times to predict AKI.

RESULTS

AKI occurred in 15 patients (13.6%). Preoperative RFR was lower in patients who experienced AKI (p < 0.001) and predicted AKI with an area under the receiver operating characteristic curve (AUC) of 0.83 (95% confidence interval [CI]: 0.70 to 0.96). Patients with preoperative RFRs not greater than 15 mL · min^-1 · 1.73 m^-2 were 11.8 times more likely to experience AKI (95% CI: 4.62 to 29.89 times, p < 0.001). In addition, immediate postoperative cell cycle arrest biomarkers predicted AKI with an AUC of 0.87.

CONCLUSIONS

Among elective cardiac surgical patients with normal resting glomerular filtration rates, preoperative RFR was highly predictive of AKI. A reduced RFR appears to be a novel risk factor for AKI, and measurement of RFR preoperatively can identify patients who are likely to benefit from preventive measures or to select for use of biomarkers for early detection. Larger prospective studies to validate the use of RFR in strategies to prevent AKI are warranted. ClinicalTrials.gov identifier: NCT03092947, ISRCTN Registry: ISRCTN16109759.

Interchangeability and Diagnostic Accuracy of Two Assays for Total and Free Prostate-Specific Antigen: Two not Always Related Items

The variation between different PSA assays seems to influence the interpretation of individual PSA values and the clinical decisions about prostate cancer. One reason for this variability could be the different reactivity of antibodies for the various molecular forms of serum PSA; as a result, samples containing the same amount of tPSA but different proportions of fPSA can produce very different values. In this study, serum samples were collected prospectively from 152 consecutive patients referred to 2 institutions (Regional Hospital, Venice, 90 subjects; San Bortolo Hospital, Vicenza, 62 subjects) for PSA elevation and/or symptoms. Serum samples were assessed according to the manufacturers’ instructions on the following 2 analyzers: the Immulite 2000 assay (Diagnostic Products Corporation, Los Angeles, USA), which measures tPSA and fPSA, and the ADVIA Centaur (Bayer Diagnostics, Tarrytown, USA), which assays tPSA and cPSA. cPSA values were transformed into fPSA by the equation fPSA=tPSA-cPSA. When taking Immulite tPSA and f/tPSA values as 100%, ADVIA Centaur values were 92.6% and 122%, respectively, which means that 20% of patients would be classified differently according to the traditional biopsy cutoff. In conclusion, there are considerable differences between the 2 methods, which could affect clinical decisions.

Predicting Acute Kidney Injury in Intensive Care Unit Patients: The Role of Tissue Inhibitor of Metalloproteinases-2 and Insulin-Like Growth Factor-Binding Protein-7 Biomarkers

<b><i>Background:</i></b> Acute kidney injury (AKI) diagnosis is based on a rise in serum creatinine and/or fall in urine output. It has been shown that there are patients that fulfill AKI definition but do not have AKI, and there are also patients with evidence of renal injury who do not meet any criteria for AKI. Recently the innovative and emerging proteomic technology has enabled the identification of novel biomarkers that allow improved risk stratification. <b><i>Methods:</i></b> Tissue inhibitor of metalloproteinases-2 (TIMP-2), insulin-like growth factor-binding protein 7 (IGFBP7) were measured to a cohort of 719 consecutive patients admitted to Intensive Care Unit (ICU). The primary endpoint was the evaluation of clinical performances of the biomarkers focusing on the probability do develop AKI in the first 7 days. <b><i>Results:</i></b> The Kaplan-Meier analysis considering the first 7 days of ICU stay suggested a lower risk of developing AKI (<i>p</i> &#x3c; 0.0001) for patients with a negative (&#x3c;0.3; TIMP-2*IGFBP7) test. <b><i>Conclusion:</i></b> (TIMP-2*IGFBP7) at ICU admission has a good performance in predicting AKI, especially in the first 4 days in ICU.

Academy of Emergency Medicine and Care-Society of Clinical Biochemistry and Clinical Molecular Biology consensus recommendations for clinical use of sepsis biomarkers in the emergency department

Increasing evidence is emerging that the measurement of circulating biomarkers may be clinically useful for diagnosing and monitoring sepsis. Eight members of AcEMC (Academy of Emergency Medicine and Care) and eight members of SIBioC (Italian Society of Clinical Biochemistry and Laboratory Medicine) were identified by the two scientific societies for producing a consensus document aimed to define practical recommendations about the use of biomarkers for diagnosing of sepsis and managing antibiotic therapy in the emergency department (ED). The cumulative opinions allowed defining three grade A recommendations (i.e., highly recommended indications), entailing ordering modality (biomarkers always available on prescription), practical use (results should be interpreted according to clinical information) and test ordering defined according to biomarker kinetics. Additional grade B recommendations (i.e., potentially valuable indications) entailed general agreement that biomarkers assessment may be of clinical value in the diagnostic approach of ED patients with suspected sepsis, suggestion for combined assessment of procalcitonin (PCT) and Creactive protein (CRP), free availability of the selected biomarker(s) on prescription, adoption of diagnostic threshold prioritizing high negative predictive value, preference for more analytically sensitive techniques, along with potential clinical usefulness of measuring PCT for monitoring antibiotic treatment, with serial testing defined according to biomarker kinetics. PCT and CRP were the two biomarkers that received the largest consensus as sepsis biomarkers (grade B recommendation), and a grade B recommendation was also reached for routine assessment of blood lactate. The assessment of biomarkers other than PCT and CRP was discouraged, with exception of presepsin for which substantial uncertainty in favor or against remained.

Laboratory testing in the emergency department: An Italian Society of Clinical Biochemistry and Clinical Molecular Biology (SIBioC) and Academy of Emergency Medicine and Care (AcEMC) consensus report

The mainstay of patient-oriented laboratory testing in emergency settings entails selecting number and type of tests according to valid criteria of appropriateness. Since the pattern of urgent tests requesting is variable across different institutions, we designed a joined survey between the Academy of Emergency Medicine and Care (AcEMC) and the Italian Society of Clinical Biochemistry and Clinical Molecular Biology (SIBioC) for reaching tentative consensus about the most informative diagnostic tests in emergency settings. A survey, containing the most commonly performed urgent laboratory tests and the relative clinical indications, was disseminated to eight relevant members of AcEMC and eight relevant members of SIBioC. All contributors were asked to provide numerical scores for the different laboratory parameters, where 1 indicated <em>strongly recommended</em>, 2 <em>recommended in specific circumstances</em>, and 3 <em>strongly discouraged</em>. The mean results of the survey were presented as the mean of responders’ values, and the parameters were finally classified as <em>strongly recommended</em> (mean value, 1.0-1.5), <em>somehow recommended</em> (mean value, 1.5-2.0), <em>discouraged</em> (mean value, 2.0-2.5) and <em>strongly discouraged</em> (mean value, 2.5-3.0). The results of the survey allowed defining a hierarchy of priority, wherein 24 tests were <em>strongly recommended</em>. The use of 5 common tests was instead <em>strongly discouraged</em>. For 16 additional parameters in the list, the consensus ranged between <em>somehow recommended</em> and <em>discouraged</em>. We hope that results presented in this joint AcEMC-SIBioC consensus document may help harmonizing panel of tests and requesting patters in emergency setting, at least at a national level.

Total laboratory automation: Do stat tests still matter?

During the past decades the healthcare systems have rapidly changed and today hospital care is primarily advocated for critical patients and acute treatments, for which laboratory test results are crucial and need to be always reported in predictably short turnaround time (TAT). Laboratories in the hospital setting can face this challenge by changing their organization from a compartmentalized laboratory department toward a decision making-based laboratory department. This requires the implementation of a core laboratory, that exploits total laboratory automation (TLA) using technological innovation in analytical platforms, track systems and information technology, including middleware, and a number of satellite specialized laboratory sections cooperating with care teams for specific medical conditions. In this laboratory department model, the short TAT for all first-line tests performed by TLA in the core laboratory represents the key paradigm, where no more stat testing is required because all samples are handled in real-time and (auto)validated results dispatched in a time that fulfills clinical needs. To optimally reach this goal, laboratories should be actively involved in managing all the steps covering the total examination process, speeding up also extra-laboratory phases, such sample delivery. Furthermore, to warrant effectiveness and not only efficiency, all the processes, e.g. specimen integrity check, should be managed by middleware through a predefined set of rules defined in light of the clinical governance.

Laboratory testing in the emergency department: an Italian Society of Clinical Biochemistry and Clinical Molecular Biology (SIBioC) and Academy of Emergency Medicine and Care (AcEMC) consensus report

Background:

The mainstay of patient-oriented laboratory testing in emergency settings entails selecting a number and the type of tests according to valid criteria of appropriateness. Since the pattern of urgent tests requesting is variable across different institutions, we designed a joined survey between the Academy of Emergency Medicine and Care (AcEMC) and the Italian Society of Clinical Biochemistry and Clinical Molecular Biology (SIBioC) for reaching tentative consensus about the most informative diagnostic tests in emergency settings.

Methods:

A survey, containing the most commonly ordered urgent laboratory tests and the relative clinical indications, was disseminated to eight relevant members of AcEMC and eight relevant members of SIBioC. All contributors were asked to provide numerical scores for the different laboratory parameters, where 1 indicated “strongly recommended”, 2 “recommended in specific circumstances”, and 3 “strongly discouraged”. The mean results of the survey were presented as the mean of responders’ values, and the parameters were finally classified as “strongly recommended” (mean value, 1.00–1.49), “weakly recommended” (mean value, 1.50–1.99), “discouraged” (mean value, 2.00–2.49) and “strongly discouraged” (mean value, 2.50–3.00).

Results:

The results of the survey allowed defining a hierarchy of priority, wherein 24 tests were “strongly recommended”. The use of five common tests was instead “strongly discouraged”. For 16 additional parameters in the list, the consensus ranged between “weakly recommended” and “discouraged”.

Conclusions:

We hope that results presented in this joint AcEMC-SIBioC consensus document may help harmonizing panel of tests and requesting patterns in emergency setting, at least at a national level.

Elevated Levels of Procalcitonin and Interleukin-6 are Linked with Postoperative Complications in Cardiac Surgery

BACKGROUND

Cardiac surgery-associated acute kidney injury is a frequent and serious postoperative complication of cardiac surgery and is associated with an increased risk of morbidity, mortality, and length stay. In this study, we hypothesized that persistent elevation in inflammation in the first 48 h might be a powerful predictor of clinical outcome. Our aim was to elucidate the usefulness of interleukin-6 and procalcitonin postoperative levels in predicting mortality and renal complications in cardiac surgery patients.

METHODS

A total of 122 cardiac surgery patients were enrolled. Procalcitonin and interleukin-6 concentrations were measured on the second postoperative day, and their levels were evaluated versus a number of conditions and endpoints.

RESULTS

Procalcitonin has a good predictive value for adverse renal outcome (p < 0.05). Interleukin-6 has a good predictive value for 30 days and overall mortality in cardiac surgery population (p < 0.05). We did not observe a significant difference in procalcitonin and interleukin-6 levels among patients with different types of surgery and different extracorporeal circulation time, but the levels of both the molecules increase significantly depending on number of transfusions received by patients (p < 0.01).

CONCLUSION

We speculated that procalcitonin and interleukin-6 could be two effective biomarkers. There is a possibility of having a combined inflammatory multi-biomarker panel, with procalcitonin for predicting renal outcome and interleukin-6 for predicting mortality.

Blood venous sample collection: Recommendations overview and a checklist to improve quality

The extra-analytical phases of the total testing process have substantial impact on managed care, as well as an inherent high risk of vulnerability to errors which is often greater than that of the analytical phase. The collection of biological samples is a crucial preanalytical activity. Problems or errors occurring shortly before, or soon after, this preanalytical step may impair sample quality and characteristics, or else modify the final results of testing. The standardization of fasting requirements, rest, patient position and psychological state of the patient are therefore crucial for mitigating the impact of preanalytical variability. Moreover, the quality of materials used for collecting specimens, along with their compatibility, can guarantee sample quality and persistence of chemical and physical characteristics of the analytes over time, so safeguarding the reliability of testing. Appropriate techniques and sampling procedures are effective to prevent problems such as hemolysis, undue clotting in the blood tube, draw of insufficient sample volume and modification of analyte concentration. An accurate identification of both patient and blood samples is a key priority as for other healthcare activities. Good laboratory practice and appropriate training of operators, by specifically targeting collection of biological samples, blood in particular, may greatly improve this issue, thus lowering the risk of errors and their adverse clinical consequences. The implementation of a simple and rapid check-list, including verification of blood collection devices, patient preparation and sampling techniques, was found to be effective for enhancing sample quality and reducing some preanalytical errors associated with these procedures. The use of this tool, along with implementation of objective and standardized systems for detecting non-conformities related to unsuitable samples, can be helpful for standardizing preanalytical activities and improving the quality of laboratory diagnostics, ultimately helping to reaffirm a "preanalytical" culture founded on knowledge and real risk perception.

Procalcitonin and Interleukin-6 Levels: Are They Useful Biomarkers in Cardiac Surgery Patients?

BACKGROUND/AIM

Cardiac surgery-associated acute kidney injury is an independent predictor of chronic renal disease and mortality. The scope of this study was to determine the utility of procalcitonin (PCT) and plasma interleukin-6 (IL-6) levels in predicting renal outcome and mortality in these patients.

METHODS

PCT and plasma IL-6 levels of 122 cardiac surgery patients were measured at 48 h after the surgical procedure. Primary endpoints were adverse renal outcome and mortality. Secondary endpoints were length of stay, bleeding, and number of transfusions.

RESULTS

PCT was found to be a better predictor of adverse renal outcome than IL-6. IL-6 seemed to be a better predictor of both 30-day and overall mortality than PCT. Neither PCT nor IL-6 levels were found to be good predictors of intensive care unit stay and bleeding.

CONCLUSION

PCT may be considered a good predictor of adverse renal outcome in cardiac surgery patients, whereas IL-6 seems to possess a good predictive value for mortality in this population of patients.

A comparison of three commercial platforms for urinary NGAL in critically ill adults

BACKGROUND

Early biomarkers for acute kidney injury (AKI) diagnosis are needed since an increase in serum creatinine levels is a late marker. Neutrophil gelatinase-associated lipocalin (NGAL) is one of the most promising AKI biomarkers. Prior to routine clinical use, it is necessary to evaluate and validate a high-throughput commercially available method for NGAL detection. The aim of this study was to do an independent validation and comparison of the analytical performance of three different commercially available urine NGAL (uNGAL) assays.

METHODS

Urine samples (n=110) were obtained from various patient groups with and without AKI. All urine samples were processed using Architect NGAL assay, Siemens Advia® 2400 NGAL test, and Siemens Dimension Vista® NGAL Test™, based on the three different platforms.

RESULTS

Overall, there was good agreement among the three assays: Spearman's rank correlation coefficient between Architect and Vista was 0.989 (95% confidence interval [CI], 0.983-0.993), between Architect and Advia, 0.962 (95% CI, 0.937-0.977), between Vista and Advia 2400, 0.975 (95% CI, 0.961-0.984). We observed a negative bias of Architect compared with the other assays: comparing Architect to Vista, the mean bias was -55.7 ng/mL (95% CI, -74.3 to -37.0 ng/mL); comparing Architect to Advia 2400, the mean bias was -40.9 ng/mL (95% CI, -56.4 to -25.4 ng/nL). The bias is proportional to the concentration of uNGAL and is more pronounced at higher levels, while irrelevant near the tested cutoff levels of 100 and 190 ng/mL. Comparing Vista and Advia 2400, the mean bias was 10.1 ng/mL (95% CI, 1.5-18.8 ng/mL). Intra-assay imprecision was generally acceptable across all assays; coefficient of variation ranged from 0.8% to 5.3%.

CONCLUSIONS

All three methods for uNGAL showed acceptable performance for the tested parameters and are comparable with each other at clinically relevant cutoffs. However, Architect yields lower results than the other two methods, with a bias more pronounced at higher uNGAL concentrations, suggesting additional standardization efforts will likely be necessary to better harmonize the uNGAL methods at various clinically relevant cutoffs.

Access to scientific information. A national survey of the Italian Society of Clinical Biochemistry and Laboratory Medicine (SIBioC)

BACKGROUND

Digital libraries are typically used for retrieving and accessing articles in academic journals and repositories. Previous studies have been published about the performance of various biomedical research platforms, but no information is available about access preferences.

METHODS

A six-question survey was designed by the Italian Society of Clinical Biochemistry and Laboratory Medicine (SIBioC) using the platform Google Drive, and made available for 1 month to the members of the society. The information about the survey was published on the website of SIBioC and also disseminated by two sequential newsletters.

RESULTS

Overall, 165 replies were collected throughout the 1-month survey availability. The largest number of replies were provided by laboratory professionals working in the national healthcare system (44.2%), followed by those working in private facilities (13.9%), university professors (12.7%) and specialization training staff (12.7%). The majority of responders published zero to one articles per year (55.2%), followed by two to five articles per year (37.6%), whereas only 7.3% published more than five articles per year. A total of 34.5% of the responders consulted biomedical research platforms on weekly basis, followed by 33.9% who did so on daily basis. PubMed/Medline was the most accessed scientific database, followed by Scopus, ISI Web of Science and Google Scholar. The impact factor was the leading reason when selecting which journal to publish in. The most consulted journals in the field of laboratory medicine were Clinical Chemistry and Laboratory Medicine and Biochimica Clinica.

CONCLUSIONS

This survey provides useful indications about the personal inclination towards access to scientific information in our country.

Multicenter Comparison of Seven 25OH Vitamin D Automated Immunoassays

BACKGROUND

The measurement of 25OH vitamin D continues to grow in clinical laboratories. The aim of this multi-center study was to compare the results of seven automated commercial immunoassays with a reference HPLC technique.

METHODS

One hundred and twenty consecutive outpatient serum samples were centrifuged, divided in aliquots, frozen and shipped to the participating laboratories. 25OH Vitamin D was measured with a reference HPLC system and with seven automated commercial immunoassays (Roche Cobas E601, Beckman Coulter Unicel DXI 800, Ortho Vitros ES, DiaSorin Liaison, Siemens Advia Centaur, Abbott Architect i System and IDS iSYS).

RESULTS

Compared to the reference method, the regression coefficients ranged from 0.923 to 0.961 (all p<0.001). The slope of Deming fit ranged from 0.95 to 1.06, whereas the intercept was comprised between -15.2 and 9.2 nmol/L. The bias from the reference HPLC technique varied from -14.5 to 8.7 nmol/L. The minimum performance goal for bias was slightly exceeded by only one immunoassay. The agreement between HPLC and the different immunoassays at 50 nmol/L 25OH Vitamin D varied between 0.61 and 0.85 (all p<0.001). The percentage of samples below this cut-off was significantly different with only one immunoassay.

CONCLUSIONS

The excellent correlation with the reference HPLC technique attests that all seven automated immunoassays may be reliably used for routine assessment of 25OH-D in clinical laboratories. The significant bias among the different methods seems mostly attributable to the lack of standardization and calls for additional efforts for improving harmonization of 25OH-D immunoassays.

Understanding Bland Altman analysis

In a contemporary clinical laboratory it is very common to have to assess the agreement between two quantitative methods of measurement. The correct statistical approach to assess this degree of agreement is not obvious. Correlation and regression studies are frequently proposed. However, correlation studies the relationship between one variable and another, not the differences, and it is not recommended as a method for assessing the comparability between methods.
In 1983 Altman and Bland (B&A) proposed an alternative analysis, based on the quantification of the agreement between two quantitative measurements by studying the mean difference and constructing limits of agreement.
The B&A plot analysis is a simple way to evaluate a bias between the mean differences, and to estimate an agreement interval, within which 95% of the differences of the second method, compared to the first one, fall. Data can be analyzed both as unit differences plot and as percentage differences plot.
The B&A plot method only defines the intervals of agreements, it does not say whether those limits are acceptable or not. Acceptable limits must be defined a priori, based on clinical necessity, biological considerations or other goals.
The aim of this article is to provide guidance on the use and interpretation of Bland Altman analysis in method comparison studies.