Reactogenicity and Peak Anti-RBD-S1 IgG Concentrations in Individuals with No Prior COVID-19 Infection Vaccinated with Different SARS-CoV-2 Vaccines

OBJECTIVE

To investigate the association of immune response with vaccination adverse effects at peak anti-receptor-binding domain spike subunit 1 (anti-RBDS1) IgG after full vaccination with Comirnaty, Spikevax, or Vaxzevria.

METHODS

Anti-RBDS1 IgG concentrations after vaccination were determined in healthy adults vaccinated with the Comirnaty, Spikevax, and Vaxzevria vaccines. The association of reactogenicity and peak antibody response after vaccination was tested.

RESULTS

Anti-RBDS1 IgG values were significantly higher in the Comirnaty and Spikevax group, compared with the Vaxzevria group (P < .001). Fever and muscle pain were found to be significant independent predictors of peak anti-RBDS1 IgG in the Comirnaty and Spikevax groups (P = .03 and P = .02, respectively). The multivariate model, adjusted for covariates, showed that no association between reactogenicity and peak antibody concentrations was found in the Comirnaty, Spikevax, and Vaxzevria groups.

CONCLUSIONS

No association between reactogenicity and peak anti-RBDS1 IgG after vaccination with the Comirnaty, Spikevax, and Vaxzevria vaccine was found.

YKL-40 as a biomarker in various inflammatory diseases: A review

YKL-40 or Chitinase-3-Like Protein 1 (CHI3L1) is a highly conserved glycoprotein that binds heparin and chitin in a non-enzymatic manner. It is a member of the chitinase protein family 18, subfamily A, and unlike true chitinases, YKL-40 is a chitinase-like protein without enzymatic activity for chitin. Although its accurate function is yet unknown, the pattern of its expression in the normal and disease states suggests its possible engagement in apoptosis, inflammation and remodeling or degradation of the extracellular matrix. During an inflammatory response, YKL-40 is involved in a complicated interaction between host and bacteria, both promoting and attenuating immune response and potentially being served as an autoantigen in a vicious circle of autoimmunity. Based on its pathophysiology and mechanism of action, the aim of this review was to summarize research on the growing role of YKL-40 as a persuasive biomarker for inflammatory diseases' early diagnosis, prediction and follow-up (e.g., cardiovascular, gastrointestinal, endocrinological, immunological, musculoskeletal, neurological, respiratory, urinary, infectious) with detailed structural and functional background of YKL-40.

Comparison of three different protocols for obtaining hemolysis

OBJECTIVES

Hemolysis is associated with erroneous or delayed results. Objectives of the study were to compare four different methods for obtaining hemolysis in vitro on three different analyzers.

METHODS

Hemolysis was prepared with addition of pure hemoglobin into serum pool, osmotic shock, aspiration through blood collection needle, freezing/thawing of whole blood. Biochemistry parameters were measured in duplicate at Architect c8000 (Abbott, Abbott Park, USA), Beckman Coulter AU680 (Beckman Coulter, Brea, USA) and Cobas 6000 c501 (Roche, Mannheim, Germany), according to manufacturers' declarations. Cut-off value was defined as the highest value of H index with corresponding bias lower than acceptance criteria.

RESULTS

We were not able to obtain results with freezing protocol. On all three platforms, lowest number of analytes were sensitive to hemolysis at H=0.5 using method of adding free hemoglobin. When osmotic shock was used, cut-off values for the most analytes were generally met at lower values. Hemolysis significantly interfered with measurement of potassium and lactate dehydrogenase (LD) at H=0.5 on all platforms. The most of the tested analytes had the lowest acceptable H index when aspiration method was used. At the low level of hemolysis (H=0.8) glucose, sodium, potassium, chloride, phosphate, and LD were affected on all analyzers, with some additional analytes depending on the manufacturer.

CONCLUSIONS

Hemolysis interference differs on different analyzers and according to protocol for obtaining hemolysis. Aspiration method was generally the most sensitive to hemolysis interference, while addition of free Hb was the most resistant.

Serum Calprotectin Is a Valid Biomarker in Distinction of Bacterial Urinary Tract Infection From Viral Respiratory Illness in Children Under 3 Years of Age

BACKGROUND

Febrile illnesses in young children can be a major diagnostic challenge, despite the routine use of various laboratory markers. Recent advancements in the understanding of inflammatory processes have highlighted the role of calprotectin, a heterodimer consisting of S100A8 and S100A9 proteins, with many studies suggesting its clinical value as a biomarker of inflammation. This research aimed to evaluate the usefulness of serum calprotectin (sCal) as a biomarker of urinary tract infection (UTI), which was due to its high pooled prevalence and feasibility of urine culture as a diagnostic reference standard selected for a model of bacterial infection in children.

METHODS

Febrile children aged 0-36 months with suspected UTI based on positive urinalysis or viral respiratory tract infection were included. Children with significant bacteriuria in urine culture were labeled as cases (n = 58), while those with confirmed viral infection (n = 51), as well as those with suspected UTI but sterile urine culture who went on to develop symptoms consistent with viral respiratory infection (n = 7), were labeled as controls. sCal levels were determined by a commercial immunoassay. Conventional inflammation markers (C-reactive protein, procalcitonin, white blood cell count, absolute neutrophil count, and neutrophil percentage) were measured on the day of the clinical examination. Differences in measured inflammatory markers between cases and controls were analyzed with Mann-Whitney U-test. ROC analysis reported cut-off values with the best sensitivity and specificity to distinguish bacterial UTI from viral respiratory infection.

RESULTS

All analyzed inflammatory biomarkers, including sCal, were significantly higher in cases than in controls. Median concentration of sCal was 4.97 μg/mL (IQR 3.43-6.42) and 2.45 μg/mL (IQR 1.63-3.85) for cases and controls, respectively (p < 0.001). For identifying bacterial UTI, sensitivity and specificity of sCal were 77.6 and 69.0%, respectively, at an adjusted cut-off point of >3.24 μg/mL (AUC 80.2%).

CONCLUSION

sCal could have substantial added value in the management of a child with fever and positive urinalysis and is a promising biomarker in distinction between bacterial UTI and viral respiratory causes of febrile illness in children under the age of 3 years.

The Increased Levels of Fecal Calprotectin in Children With Active Enthesitis Related Arthritis and MRI Signs of Sacroiliitis: The Results of a Single Center Cross-Sectional Exploratory Study in Juvenile Idiopathic Arthritis Patients

Enthesitis related arthritis (ERA) is a specific subtype of juvenile idiopathic arthritis (JIA), often regarded as an undifferentiated form of juvenile spondyloarthritis (jSpA). While gut is increasingly recognized as origin and/or target of inflammation in adult onset spondyloarthritis (SpA), the incidence of gut involvement in ERA patients is largely unknown. The aim of this study was to measure the concentration of fecal calprotectin (fCAL), a surrogate marker of gut inflammation, in patients with different subtypes of JIA, as well as to correlate the results with various demographic, clinical, laboratory, imaging, and treatment characteristics. The cross-sectional exploratory study involving 71 patients with ERA, other forms of JIA and children complaining musculoskeletal symptoms was therefore conducted. Along with fCAL assessment, a detailed clinical and laboratory examination was performed, including the calculation of a composite disease activity scores. Moreover, MRI of the sacroiliac joints was performed in all ERA and other patients complaining of low back pain. The median concentration of fCAL was highest in ERA patients (33.2 mg/kg, p = 0.02), with a significant difference between those with inactive and active disease (20.0 vs. 57.4, p = 0.01), as well as those with and without MRI signs of sacroiliitis (22.6 vs. 54.3, p = 0.04). The fCAL did not differ depending on the NSAID use (23 vs. 20, p = 0.18), although weak correlation was observed with the treatment duration (r = 0.25, p = 0.03). In conclusion, our findings indicate that a parallel inflammation in musculoskeletal system and gut can occur not just in adults with SpA, but in children with ERA as well.

Comparison of diagnostic accuracy for eight SARS-CoV-2 serological assays

Introduction

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological tests have been suggested as an additional diagnostic tool in highly suspected cases with a negative molecular test and determination of seroprevalence in population. We compared the diagnostic performance of eight commercial serological assays for IgA, IgM, and IgG antibodies to the SARS-CoV-2 virus.

Materials and methods

The comparison study was performed on a total of 76 serum samples: 30 SARS-CoV-2 polymerase chain reaction (PCR)-negative and 46 SARS-CoV-2 PCR-positive patients with asymptomatic to severe disease and symptoms duration from 3-30 days. The study included: three rapid lateral flow immunochromatographic assays (LFIC), two enzyme-linked immunosorbent assays (ELISA), and three chemiluminescence immunoassays (CLIA).

Results

Agreement between IgM assays were minimal to moderate (kappa 0.26 to 0.63) and for IgG moderate to excellent (kappa 0.72 to 0.92). Sensitivities improved with > 10 days of symptoms and were: 30% to 89% for IgM; 89% to 100% for IgG; 96% for IgA; 100% for IgA/IgM combination; 96% for total antibodies. Overall specificities were: 90% to 100% for IgM; 85% to 100% for IgG; 90% for IgA; 70% for IgA/IgM combination; 100% for total antibodies. Diagnostic accuracy for IgG ELISA and CIA assays were excellent (AUC ≥ 0.90), without significant difference. IgA showed significantly better diagnostic accuracy than IgM (P < 0.001).

Conclusion

There is high variability between IgM assays independently of the assay format, while IgG assays showed moderate to perfect agreement. The appropriate time for testing is crucial for the proper immunity investigation.

In sickness and in health: pivotal role of vitamin D

Within the last several years, frequency of vitamin D testing has multiplied substantially all over the world, since it has been shown to have an important role in many diseases and conditions. Even though liquid chromatography - tandem mass spectrometry (LC-MS/MS) has been identified as "gold standard" method for vitamin D measurement, most laboratories still use immunochemistry methods. Besides analytical problems (hydrophobicity, low circulating concentrations, ability to bind to lipids, albumins and vitamin D binding protein, presence of multiple vitamin D metabolites and variable ratios of 25(OH)D₂ and 25(OH)D₃ in the blood), vitamin D shows great preanalytical variability, since its concentration is drastically influenced by seasonal changes, exposure to sun, type of clothes or sun block creams. Vitamin D is mostly measured in serum or plasma, but new studies are showing importance of measuring vitamin D in pleural effusions, breast milk, urine, synovial fluid and saliva. Besides the main role in calcium homeostasis and bone metabolism, many studies linked vitamin D deficiency with cancer, cardiovascular diseases, diabetes, fertility and many other conditions. However, even though initial observational studies indicated that supplementation with vitamin D might be beneficial in disease development and progression; first results of well-designed randomized controlled prospective studies did not find differences in frequency of cardiovascular events or invasive cancer between patients taking vitamin D supplementation compared to placebo. In the light of these recent findings, validity of excessive vitamin D testing remains an open question.

Long-term stability of clinically relevant chemistry analytes in pleural and peritoneal fluid

Introduction

Our aim was to investigate the stability of clinically relevant analytes in pleural and peritoneal fluids stored in variable time periods and variable storage temperatures prior to analysis.

Materials and methods

Baseline total proteins (TP), albumin (ALB), lactate dehydrogenase (LD), cholesterol (CHOL), triglycerides (TRIG), creatinine (CREA), urea, glucose and amylase (AMY) were measured using standard methods in residual samples from 29 pleural and 12 peritoneal fluids referred to our laboratory. Aliquots were stored for 6 hours at room temperature (RT); 3, 7, 14 and 30 days at - 20°C. At the end of each storage period, all analytes were re-measured. Deviations were calculated and compared to stability limits (SL).

Results

Pleural fluid TP and CHOL did not differ in the observed storage periods (P = 0.265 and P = 0.170, respectively). Statistically significant differences were found for ALB, LD, TRIG, CREA, urea, glucose and AMY. Peritoneal fluid TP, ALB, TRIG, urea and AMY were not statistically different after storage, contrary to LD, CHOL, CREA and glucose. Deviations for TP, ALB, CHOL, TRIG, CREA, urea and AMY in all storage periods tested for both serous fluids were within the SL. Deviations exceeding SL were observed for LD and glucose when stored for 3 and 7 days at - 20°C, respectively.

Conclusions

TP, ALB, CHOL, TRIG, CREA, urea and AMY are stable in serous samples stored up to 6 hours at RT and/or 30 days at - 20°C. Glucose is stable up to 6 hours at RT and 3 days at - 20°C. The stability of LD in is limited to 6 hours at RT.

Lower concentration of vitamin D is associated with lower DAS28 and VAS-pain scores in patients with inflammatory rheumatic diseases treated with infliximab: a pilot study

Vitamin D is beneficial in patients with immune-mediated rheumatic diseases as it has been shown that it lowers the incidence risk and the level of inflammation. To examine the association between clinical outcomes and initial 25-hydroxyvitamin D [25(OH)D] concentrations in patients with the immune-mediated rheumatic diseases treated with infliximab for 9 months. This study was performed in patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) treated with infliximab for at least 38 weeks. Disease activity was assessed using Disease Activity Score (DAS28) for RA and PsA and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) for AS, while the global assessment was performed using the Visual Analogue Scale (VAS). Patients were divided into 2 groups according to 25(OH)D concentration which was classified as deficient or non-deficient (below and above 50 nmol/L, respectively). Concentrations of infliximab (IFX) and C-reactive protein (CRP) were measured according to the manufacturer's instructions.This study was performed in patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) treated with infliximab for at least 38 weeks. Disease activity was assessed using Disease Activity Score (DAS28) for RA and PsA and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) for AS, while the global assessment was performed using the Visual Analogue Scale (VAS). Patients were divided into 2 groups according to 25(OH)D concentration which was classified as deficient or non-deficient (below and above 50 nmol/L, respectively). Concentrations of infliximab (IFX) and C-reactive protein (CRP) were measured according to the manufacturer's instructions. The study included 23 patients (14 with RA, 6 with AS and 3 with PsA), median age 54 years, 15 females. Vitamin D deficient and non-deficient groups had median initial concentrations of 38 and 61 nmol/L, respectively. DAS28 and pain on VAS calculated at the 2nd and 38th week showed a statistically significant decrease only in RA and PsA patients with vitamin D deficiency (P = 0.02 and 0.06, respectively). Lower initial concentration of 25(OH)D in patients treated with infliximab was associated with better improvement of clinical measures (DAS28 and VAS) of disease after 9 months of therapy.

Integrity of serum samples is changed by modified centrifugation conditions

Background Serum samples should be centrifuged for at least 10 min at 1300-2500 × g. Changed centrifugation conditions could compromise sample quality. The objective of this study was to compare the serum quality and turnaround time (TAT) using different centrifugation conditions. Methods The study was done in four different periods (A, B, C and D) at different conditions: for 10, 5 and 7 (A, B and C, respectively) at 2876 × g, and 7 (D) min at 4141 × g. Sample quality was assessed as the proportion of samples with: (a) aspiration errors, (b) H index >0.5 g/L and (c) suppressed reports of potassium (K) due to hemolysis. TAT was calculated for emergency samples. The proportions of samples (a), (b) and (c) were compared according to period A. Results The number of aspiration errors was significantly higher in samples centrifuged at 2876 × g for 5 min (p = 0.021) and remained unchanged when centrifuged for 7 min (p = 0.066 and 0.177, for periods C and D, respectively). In periods B, C and D, the proportion of samples with hemolysis was higher than that in period A (p-values 0.039, 0.009 and 0.042, respectively). TAT differed between all periods (p < 0.001), with the lowest TAT observed for B and D. The lowest number of samples exceeding 60-min TAT was observed in period D (p = 0.011). Conclusions The integrity of serum samples is changed with different centrifugation conditions than those recommended. Our study showed that shorter centrifugation at higher force (7 min at 4141 × g) significantly decreases TAT, with unchanged proportion of samples with aspiration errors.

Patient's knowledge and awareness about the effect of the over-the-counter (OTC) drugs and dietary supplements on laboratory test results: a survey in 18 European countries

Background Nowadays over-the-counter (OTC) drugs and dietary supplements are widely used. Their use can have a significant impact on the validity of laboratory results. The aim of this multicenter European study was to determine the frequency of consumption of various dietary products and OTC drugs among patients and explore their level of knowledge and awareness about the potential impact of various products on laboratory test results. Methods Eighteen European countries participated in this study. The survey was carried out anonymously on a subsequent series of outpatients (n=200) in each participating country. Included were patients who were referred to the laboratory for blood sampling and who voluntarily agreed to participate in the study. The survey included questions about the frequency of consumption of various products, awareness of the importance of informing physicians and laboratory staff about it and information about influence of preanalytical factors in general on laboratory test results. Results In total, 68% of patients were regularly taking at least one OTC drug or dietary supplement. The frequency of patients consuming at least one OTC drug or dietary supplement differed between countries (p=0.001). Vitamins (38%), minerals (34%), cranberry juice (20%), acetylsalicylic acid (ASA) (17%) and omega fatty acids (17%) were the most commonly used in our study. Conclusions The use of various OTC drugs and dietary supplements is highly prevalent in Europe and patients are often not willing to disclose this information to the laboratory staff and ordering physician. The education of both patients and healthcare staff is needed.

Ascorbic acid in urine still compromises urinalysis results

Background

The aim of this work was to determine the frequency of ascorbic acid-positive urine samples and to evaluate the potential risk on patient safety.

Materials and methods

A total of  27,856 samples submitted for urinalysis in previous year were retrospectively analysed from the laboratory information system. Urinalysis was done on Iris IQ200 analyzer using 11-parameter iChem Velocity test strips. Risk analysis combined the impact of potentially erroneous results (due to ascorbic acid interference) on patient safety (severity – S) with their frequency (occurrence – O). Potential risk was identified as high, intermediate and low.

Results

One thousand one hundred and ninety-nine (4.3%) and 1646 (5.9%) samples were mildly (20 mg/dL, 1+) and highly positive (40 mg/dL, 2+) for ascorbic acid, respectively. Severity (S1 to S5) was assigned to four possible errors: false-negative glucose (U-Glc: S2), blood (U-Hb: S5), nitrite (U-Nit: S4) and bilirubin (U-Bil: S1). Based on the frequency of errors, occurrence was categorized as: O2 for U-Glc, and O3 for U-Bil, U-Nit and U-Hb. The risk analysis matrix revealed that false-negative U-Hb was associated with potentially high risk, false-negative U-Nit with intermediate risk, while false-negative U-Glc and U-Bil were associated with low risk on patient safety.

Conclusions

Positive ascorbic acid can cause potentially high risk for patient safety by missing positive blood in urine.

Precision, accuracy, cross reactivity and comparability of serum indices measurement on Abbott Architect c8000, Beckman Coulter AU5800 and Roche Cobas 6000 c501 clinical chemistry analyzers

BACKGROUND

The aim of our study was to perform verification of serum indices on three clinical chemistry platforms.

METHODS

This study was done on three analyzers: Abbott Architect c8000, Beckman Coulter AU5800 (BC) and Roche Cobas 6000 c501. The following analytical specifications were verified: precision (two patient samples), accuracy (sample with the highest concentration of interferent was serially diluted and measured values compared to theoretical values), comparability (120 patients samples) and cross reactivity (samples with increasing concentrations of interferent were divided in two aliquots and remaining interferents were added in each aliquot. Measurements were done before and after adding interferents).

RESULTS

Best results for precision were obtained for the H index (0.72%-2.08%). Accuracy for the H index was acceptable for Cobas and BC, while on Architect, deviations in the high concentration range were observed (y=0.02 [0.01-0.07]+1.07 [1.06-1.08]x). All three analyzers showed acceptable results in evaluating accuracy of L index and unacceptable results for I index. The H index was comparable between BC and both, Architect (Cohen's κ [95% CI]=0.795 [0.692-0.898]) and Roche (Cohen's κ [95% CI]=0.825 [0.729-0.922]), while Roche and Architect were not comparable. The I index was not comparable between all analyzer combinations, while the L index was only comparable between Abbott and BC. Cross reactivity analysis mostly showed that serum indices measurement is affected when a combination of interferences is present.

CONCLUSIONS

There is heterogeneity between analyzers in the hemolysis, icteria, lipemia (HIL) quality performance. Verification of serum indices in routine work is necessary to establish analytical specifications.

Visual assessment of hemolysis affects patient safety

BACKGROUND

Manual handling of hemolyzed samples is not standardized and is vulnerable to errors. This study aimed to evaluate laboratory errors due to manual handling of hemolyzed samples and to assess the risk they might have for patient safety.

METHODS

Data were retrospectively obtained from a laboratory information system for 25 emergency tests from hemolyzed samples. Hemolysis (concentration of free hemoglobin >0.5 g/L) was visually assessed by comparison with a color chart. The reference person reestimated the routinely assessed degree of hemolysis to all samples (n=3185) received in the laboratory in a 1-week period. For each test, the correct and incorrect way of handling results was determined. Risk assessment was performed according to ISO 14971 standard with five categories of risk (S1-S5) and error occurrence (O1-O5).

RESULTS

In the studied period, the emergency laboratory received 495 hemolyzed samples (15.5%) with a total of 2518 laboratory test requests (15.5%): 102 (20.6%) of the reports from hemolyzed samples had a comment on hemolysis; 31% of the test results were handled incorrectly (20.7% due to the incorrect release of the test result despite hemolysis interference and 10.3% due to unnecessary suppression), accounting for 4.8% of the total test volume. Tests with the highest combination of risk and occurrence rate were troponin T, potassium and total bilirubin.

CONCLUSIONS

Manual handling of hemolyzed samples may lead to risk of errors in reporting results for troponin T, potassium and total bilirubin, which may have an effect on clinical decision. In addition, unnecessary suppression of the sample results unaffected by hemolysis could affect patient outcome.

Implementation of the Autovalidation Algorithm for Clinical Chemistry Testing in the Laboratory Information System

Objective

Autovalidation algorithm should be properly designed with clearly defined criteria and any data that do not meet the criteria, must be reviewed and manually validated. The aim was to define the rules for autovalidation in our laboratory information system (LIS), and validate the algorithm prior to its implementation in routine laboratory work.

Methods

Autovalidation was implemented for all routine serum biochemistry tests. The algorithm included analytical measurement ranges (AMR), delta check, critical values, serum indices and all preanalytical and analytical flags from the analyzer.

Results

In the validation process 9805 samples were included, and 78.3% (7677) of all samples were autovalidated. The highest percentage of non-validated samples (54.9%) refers to those with at least one result outside the method linearity ranges (AMR criteria) while critical values were observed to be the least frequent criterion for stopping autovalidation (1.8%). Also, 38 samples were manually validated as they failed to meet the autovalidation criteria.

Conclusion

Implementation of algorithm for autovalidation in our institution resulted in the redesign of the existing LIS. This model of the autovalidation algorithm significantly decreased the number of manually validated test results and can be used as a model for introducing autovalidation in other laboratory settings.

Comparison of Enzymatic Assay for HBA1C Measurement (Abbott Architect) With Capillary Electrophoresis (Sebia Minicap Flex Piercing Analyser)

Objective

To compare the analytical performances of the enzymatic method (EM) and capillary electrophoresis (CE) for hemoglobin A1c (HbA1c) measurement.

Methods

Imprecision, carryover, stability, linearity, method comparison, and interferences were evaluated for HbA1c via EM (Abbott Laboratories, Inc) and CE (Sebia).

Results

Both methods have shown overall within-laboratory imprecision of less than 3% for International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) units (<2% National Glycohemoglobin Standardization Program [NGSP] units). Carryover effects were within acceptable criteria. The linearity of both methods has proven to be excellent (R2 = 0.999). Significant proportional and constant difference were found for EM, compared with CE, but were not clinically relevant (<5 mmol/mol; NGSP <0.5%). At the clinically relevant HbA1c concentration, stability observed with both methods was acceptable (bias, <3%). Triglyceride levels of 8.11 mmol per L or greater showed to interfere with EM and fetal hemoglobin (HbF) of 10.6% or greater with CE.

Conclusion

The enzymatic method proved to be comparable to the CE method in analytical performances; however, certain interferences can influence the measurements of each method.

Ascorbic acid-A black hole of urine chemistry screening

BACKGROUND

Study was performed in order: (i) to assess the comparability of glucose, bilirubin, hemoglobin, leukocyte esterase, and protein; (ii) to assess accuracy of glucose, bilirubin, hemoglobin, leukocyte esterase, and protein; and (iii) to evaluate interference of ascorbic acid on the glucose, bilirubin, hemoglobin, and nitrite determination using 2 different dipsticks: iChem Velocity, Iris Diagnostics and Combur-10M, Roche Diagnostics.

METHODS

Random urine specimens were included in the study. Comparability, accuracy, and ascorbic acid interference testing were performed.

RESULTS

Obtained results have shown almost perfect agreement for all parameters between 2 dipsticks in samples with negative ascorbic acid. Agreement in samples with positive ascorbic acid was not acceptable for bilirubin, protein, nitrite, and hemoglobin. Accuracy was not acceptable for hemoglobin and leukocyte esterase on both dipsticks. Ascorbic acid interference examination has shown that intensity of interference differs between dipsticks. Ascorbic acid interferes with glucose, hemoglobin, nitrite, and bilirubin at different concentrations causing false-negative results.

CONCLUSION

Obtained results indicate that it is necessary to determine diagnostic accuracy of used dipstick in order to define purpose of urinalysis. It is very important to choose dipstick with ascorbic acid indicator and to examine ascorbic acid impact on dipstick analytes independently of manufacturer claims.

Preanalytics of urine sediment examination: effect of relative centrifugal force, tube type, volume of sample and supernatant removal

INTRODUCTION

Laboratories often modify procedures recommended by the European Urinalysis Guidelines for urine sediment analysis. The aim of this study was to compare the recommended protocol with our routine laboratory procedure and to evaluate the possible impact of modifications in the relative centrifugal force, type of tube, method of supernatant aspiration and urine volume on patient's results.

MATERIAL AND METHODS

Firstly, relative centrifugal force was investigated using 20 pairs of samples examined after centrifugation at 400xg and 1358xg. In phase two, 110 samples were examined, paired as: round bottom vs conical tube (N = 46), decanting vs suction of supernatant (N = 100) and 10 mL vs 5 mL of urine sample (N = 101).

RESULTS

The number of erythrocytes, leukocytes and squamous epithelial cells was significantly lower after centrifugation at 400xg (P = 0.001, 0.002 and 0.004, respectively). The number of leukocytes was significantly lower in conical tubes (P = 0.010), after the suction of supernatant (P = 0.045) and in 5 mL urine (P < 0.001). The number of squamous epithelial cells was significantly lower after the suction of supernatant (P < 0.001) and in 5 mL urine (P < 0.001). The number of erythrocytes (P < 0.001), total non-hyaline casts (P < 0.001) and the frequency of granular casts (P = 0.039) was significantly lower in 5 mL urine.

CONCLUSION

Lower results of leukocytes, erythrocytes, squamous cells and non-hyaline casts were recorded in recommended procedures (centrifugation at 400xg, suction of supernatant, conical tube, 5 mL of sample) than in routine procedure (centrifugation at 1358xg, decanting of supernatant, round bottom tube, 10 mL) used in our laboratory.

Patient safety is not compromised by excluding microscopic examination of negative urine dipstick

Background Microscopic examination of samples with negative dipstick results is not necessary. The aims of this study were to: (i) assess the risk of excluding urine sediment examination with negative dipstick results and (ii) calculate time savings by introducing this process. Methods The risk analysis was done for samples with negative urine dipstick and positive sediment findings. Possible missed elements in sediment were defined as 21 errors. Time saving was calculated as average time for preparation and examination sediments. Data were presented as counts and percentages. Results Out of 2997 samples, negative dipstick results were reported for 926 (30.6%) samples, out of which, microscopic examinations were positive for 527 (17.6%) samples. 18/21 errors were detected, with missing <5 squamous epithelial cells (SQEC) and bacteria 1+ as the most frequent ones (22.7% and 22.4%, respectively). Errors with the intermediate risk for patients were missing to report: ≥5 SQEC, ≥5 transitional epithelial cells, ≥10 hyaline casts (11.9%, 0.21%, 0.32%, respectively). Errors associated with high risk were not detected. Estimated total time saving is more than 25 h/month. Conclusions Microscopic examination of urine samples with negative dipstick results can be excluded without risk for patients and can result with considerable time savings.

Is peritoneal dialysis causing a measurable burden of inflammatory and endothelial injury on top of metabolic syndrome?

PURPOSE

Low-grade chronic inflammation is present in patients on peritoneal dialysis (PD) and in metabolic syndrome (MS). Due to possible greater endothelial changes in dialyzed patients, inflammatory response and oxidative stress are probably stronger in patients on PD. The objective of the study was to investigate possible in between adipokines, inflammatory, endothelial and oxidative stress markers between MS patients and patients on PD.

METHODS

Concentrations of adipokines (leptin, resistin), inflammatory markers [interleukin-6 (IL-6), soluble tumor necrosis factor alpha receptor (sTNF-R), myeloperoxidase (MPO), monocyte chemoattractant protein 1 (MCP-1)] and endothelial markers [soluble intracellular adhesion molecule-1 (sICAM-1), soluble CD40 ligand (sCD40L)] were determined in 55 MS patients and 18 patients on PD, with flow cytometry, and visfatin concentration was measured with ELISA. Routine biochemistry parameters were measured on Beckman Coulter AU2700 analyzer.

RESULTS

Patients on PD have significantly higher concentration of: CRP [6.5 (3.7-12.1) versus 2.6 (1.3-4.0) mg/L, P < 0.001], IL-6 [13.83 (8.48-31.31) versus 2.05 (0.67-4.11) pg/mL, P < 0.001], MCP-1 [2172.28 (1563.84-2922.77) versus 1353.58 (1166.33-1961.70) pg/mL, P = 0.023], sTNF-R [18.25 (12.81-25.22) versus 1.23 (0.89-1.43) ng/mL, P < 0.001] and sICAM-1 [830.03 (599.21-967.02) versus 463.85 (315.25-751.71) ng/mL, P = 0.006] than subjects with MS. MS patients have higher concentrations of MPO [175.47 (120.15-231.67) versus 101.76 (53.55-186.06) ng/mL, P = 0.016] and visfatin [1.5 (0.9-2.3) versus 0.9 (0.6-1.6) ng/mL, P = 0.013].

CONCLUSION

In patients on PD, inflammatory reaction is higher than in patients with MS. On the contrary, patients with MS have stronger oxidative stress response and adipose tissue activity caused probably by the chronic low level of inflammation and underlying metabolic disorders.

Croatian laboratories have a good knowledge of the proper detection and management of hemolyzed, icteric and lipemic samples

Endogenous interferences are an important source of biased laboratory results. Hemolysis, lipemia and icteria are the main source of endogenous interference in laboratory medicine. Accreditation according to ISO 15189 improves the overall quality of the laboratory procedures. The aim of our study was i) to assess the level of knowledge of Croatian medical biochemists about the proper detection and management of hemolysis, lipemia and icteria; and ii) to identify possible differences in the level of knowledge respective to the laboratory accreditation status.

An on-line self-report survey was carried out by the Working Group for Preanalytical Phase of the Croatian Society of Medical Biochemistry and Laboratory Medicine during April to May 2015. Survey included 14 statements (Q1–Q14) about procedures for samples with interferences and participants were asked to assess the degree of agreement with the statement using a 4-point Likert scale.

The lowest level of knowledge was observed for statements Q10 (dealing with icteric sample; 40.9% participants agreed with the correct procedure), Q12 (allowable error for interference; 47.2%) and Q11 (dealing with lipemic sample; 60.1%). Almost all participants (97.4%) agreed that laboratories in Croatia should have a harmonized protocol for management of samples with interferences. Participants from accredited laboratories showed higher knowledge of hemolysis detection (p=0.031), rejection of hemolyzed sample (p<0.001), management of icteric samples (p=0.038) and allowable error for interferences (p=0.040).

Croatian laboratories have a good knowledge of the proper detection and management of hemolyzed, icteric and lipemic samples. Accreditation is associated with higher knowledge about management of samples with interferences.

How compliant are technicians with universal safety measures in medical laboratories in Croatia?--A pilot study

Introduction

This pilot study aimed to investigate the use of personal protective equipment (PPE) and compliance to the code of conduct (rules defined in institutional, governmental and professional guidelines) among laboratory technicians in Croatian medical laboratories. In addition, we explored the differences in compliance between participants of different age groups, laboratory ownership and accreditation status.

Materials and methods

An anonymous and voluntary survey with 15 questions was conducted among Croatian medical laboratory technicians (N = 217). The questions were divided into two groups: demographic characteristics and the use of PPE. The questions of the second part were graded according to the Likert scale (1-4) and an overall score, shown as median and range (min-max), was calculated for each participant. Differences between the overall scores were tested for each group of participants.

Results

The majority of participants always wear protective clothes at work, 38.7% of them always wear gloves in daily routine, more than 30.0% consume food and almost half of them drink beverages at workplace. A significantly lower overall score was found for participants working in public compared to private laboratories (36 (16-40) vs. 40 (31-40), P < 0.001). There were no statistically significant differences in overall scores for participants of different age groups (P = 0.456) and laboratory accreditation status (P = 0.081).

Conclusion

A considerable percentage of laboratory technicians in Croatian medical laboratories do not comply with safety measures. Lack of compliance is observed in all personnel regardless laboratory accreditation and participants’ age. However, those working in private laboratories adhere more to the code of conduct.

Testosterone and estradiol treatments differently affect pituitary-thyroid axis and liver deiodinase 1 activity in orchidectomized middle-aged rats

We previously reported that orchidectomy (Orx) of middle-aged rats (15-16-month-old; MA) slightly affected pituitary-thyroid axis, but decreased liver deiodinase (Dio) type 1 and pituitary Dio2 enzyme activities. At present, we examined the effects of subsequent testosterone-propionate treatment (5mg/kg; Orx+T), and compared the effects of testosterone with the effects of estradiol-dipropionate (0.06mg/kg; Orx+E) treatment. Hormones were subcutaneously administered, daily, for three weeks, while Orx and sham-operated (SO) controls received only the vehicle. The applied dose of T did not alter serum TSH, T4 and T3 concentrations in Orx- MA, though it increased TSH when administrated to Orx young adults (2.5-month-old; Orx-YA). However, pituitaries of Orx-MA+T rats had higher relative intensity of immunofluorescence (RIF) for TSHβ; in their thyroids we found increased volume and height of follicular epithelium, decreased volume of the colloid and higher RIF for T4-bound to thyroglobulin (Tg-T4). Liver Dio1 activity was increased. E-treatment did not affect serum hormone levels, pituitary RIF for TSHβ, or liver Dio1 activity in Orx-MA rats. Thyroids had decreased relative volume and height of follicular epithelium, increased relative volume of the colloid, decreased volume of sodium-iodide symporter-immunopositive epithelium and lower RIF for Tg-T4. Detected changes were statistically significant. In conclusion, androgenization enhanced pituitary TSHβ RIF, thyroid activation and liver Dio1 enzyme activity in Orx-MA, without elevating serum TSH as in Orx-YA rats. Estrogenization induced pituitary enlargement with no effect on pituitary TSHβ RIF, serum TSH or liver Dio1 activity. E also induced alterations in thyroid histology that indicate mild suppression of its functioning, and contributed to thyroid blood vessel enlargement in Orx-MA rats.

How to assess the quality of your analytical method?

Laboratory medicine is amongst the fastest growing fields in medicine, crucial in diagnosis, support of prevention and in the monitoring of disease for individual patients and for the evaluation of treatment for populations of patients. Therefore, high quality and safety in laboratory testing has a prominent role in high-quality healthcare. Applied knowledge and competencies of professionals in laboratory medicine increases the clinical value of laboratory results by decreasing laboratory errors, increasing appropriate utilization of tests, and increasing cost effectiveness. This collective paper provides insights into how to validate the laboratory assays and assess the quality of methods. It is a synopsis of the lectures at the 15th European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Continuing Postgraduate Course in Clinical Chemistry and Laboratory Medicine entitled “How to assess the quality of your method?” (Zagreb, Croatia, 24–25 October 2015). The leading topics to be discussed include who, what and when to do in validation/verification of methods, verification of imprecision and bias, verification of reference intervals, verification of qualitative test procedures, verification of blood collection systems, comparability of results among methods and analytical systems, limit of detection, limit of quantification and limit of decision, how to assess the measurement uncertainty, the optimal use of Internal Quality Control and External Quality Assessment data, Six Sigma metrics, performance specifications, as well as biological variation. This article, which continues the annual tradition of collective papers from the EFLM continuing postgraduate courses in clinical chemistry and laboratory medicine, aims to provide further contributions by discussing the quality of laboratory methods and measurements and, at the same time, to offer continuing professional development to the attendees.

Visfatin is not associated with inflammatory markers in patients on hemodialysis

BACKGROUND

Cardiovascular events are a major cause of death in patients with end-stage renal disease. Endothelial dysfunction represents a key event in atherosclerosis development and has been implicated in the pathophysiology of different forms of cardiovascular disease, including chronic kidney disease. In recent years, visfatin, a ubiquitous adipokine, has been described as a potent marker of endothelial inflammation and dysfunction. The aim of the study was to investigate the association of visfatin with well-known markers of inflammation and endothelial dysfunction.

METHODS

Serum and plasma samples from 66 patients (40 males and 26 females) treated by hemodialysis were analysed for visfatin, fibrinogen, CRP, PAI-1 levels. Visfatin was determined by ELISA method while CRP, fibrinogen and PAL-1 were obtained by standard laboratory methods.

RESULTS

We observed statistically significant correlation between visfatin level and fibrinogen (r = 0.51; p = 0.008) and the time on dialysis in female patients (r = 0.70; p < 0.001). PAI-1 and CRP did not correlate with visfatin in males nor in females.

CONCLUSIONS

Visfatin is correlated with time on dialysis and with fibrinogen only in female dialysis patients. To confirm this, further studies are needed with a higher number of patients.

Low level of adherence to instructions for 24-hour urine collection among hospital outpatients

INTRODUCTION

We hypothesized that patients are poorly informed about proper procedure for 24-hour urine specimen collection and its relevance in determination of biochemical analytes, despite availability of leaflets and webpage with instruction for collection. The aim of this survey was to question outpatients how well are they informed about procedure of 24-hour urine specimen collection.

MATERIALS AND METHODS

The survey with 10 questions was done in outpatient laboratory of University Department of Chemistry, Medical School University Hospital Sestre Milosrdnice, Zagreb, Croatia. The study included 59 patients with collected 24-hour urine sample who have consented to participate in the survey.

RESULTS

Out of 59 participants, most of them (0.97) were older than 40 years. Internet was not recognized as a source of information (1/59). Almost one third of the patients have changed their drinking habits to collect more urine volume. Although most of the patients (0.60) were aware that the bottle of water is the best choice for the container, almost half of them were collected urine samples in the plastic soft drink bottle. Laboratory staff and physicians often have given information about proper collection procedure, but that information was insufficient.

CONCLUSIONS

Patients are usually not aware of importance of proper preanalytical procedure for collecting urine specimen and how improper collection could affect results of requested tests. Education of outpatients, general practitioners and laboratory staff is needed in order to improve sample quality and trueness of results.

Antibodies to mutated citrullinated vimentin and antibodies to cyclic citrullinated peptides in juvenile idiopathic arthritis

BACKGROUND

The goal of the study was to assess the presence of antibodies to mutated citrullinated vimentin (anti-MCV) and cyclic citrullinated peptides (anti-CCP) in patients with juvenile idiopathic arthritis (JIA) compared with patients with other juvenile onset rheumatic diseases.

METHODS

The study included 56 patients who fulfilled the International League of Associations for Rheumatology (ILAR) classification criteria for JIA, and 17 control patients with other juvenile onset rheumatic diseases. Data on six core outcome variables and the Sharp score were collected for patients with JIA. Sera and synovial fluid, if available, were tested for anti-CCP and anti-MCV antibodies using a commercial enzyme-linked immunosorbent assay (ELISA).

RESULTS

Anti-MCV antibodies were positive in 3/56 (5.4%) and anti-CCP in 1/56 (1.8%) of patients with JIA. Two out of three anti-MCV positive patients (one of them also anti-CCP positive) were found to be rheumatoid factor (RF)-positive with polyarticular disease. Within the control group, anti-MCV was positive in 4/17 (23.5%) patients, while anti-CCP positivity was not observed. No correlation between anti-MCV with anti-CCP antibody levels was found for any of the six core outcome variables or for the adapted Sharp score.

CONCLUSIONS

Our results show that antibodies targeting citrullinated proteins are not a useful diagnostic marker for JIA, but can indicate severe patterns of disease in JIA.

Efficiency of test report delivery to the requesting physician in an outpatient setting: an observational study

BACKGROUND

Clinical laboratories accredited according to ISO 15189 quality standards are obliged to implement and continuously monitor quality indicators for evaluation of the laboratory's contribution to patient care. Reporting laboratory results to the requesting physician is one important phase of the clinical laboratory testing process. Failure to report results may indicate the ineffectiveness of the laboratory service. We aimed to analyze the proportion and type of laboratory reports for outpatients that were not delivered to the requesting physician.

METHODS

This retrospective observational study was conducted during an 11-month period from January to December 2007 at our outpatient biochemistry laboratory unit. Data on demographic characteristics, request types and laboratory findings for all uncollected reports were retrieved from the laboratory information system and compared with one random 2-week representative period.

RESULTS

During the study period our laboratory issued 22,445 patient reports with more than 150,000 biochemistry analyses. Of these, 464 (2.1%) were uncollected laboratory reports. When compared to the representative period, patients who never collected their laboratory reports were younger (p<0.001) or suffering from some chronic disease. Routine biochemistry tests were the most prevalent (>50%). The majority of routine biochemistry tests were almost equally represented during the study and representative period, while molecular diagnostic tests were several times more frequently uncollected (p<0.001). Reports with electrolytes, metabolites and glucose were the least likely to be uncollected (p<0.001). The total cost for those tests was 30% of the average monthly laboratory budget.

CONCLUSIONS

A significant amount of the laboratory budget is wasted for tests that never reach the requesting physician. Such misutilization of the laboratory reveals the substantial lack of medical necessity for test requests. Further studies are needed to explore the possible efficiency of the various interventions in reducing the volume of unnecessary and erroneous testing.

[The condition of circulatory system in children and adolescents with ESRD treated by continuous ambulatory peritoneal dialysis and hemodialysis]

Cardio-vascular abnormalities appear very often in end-stage renal failure patients. Because of this we have examined 54 patients, children and adolescents, 35 patients underwent haemodialysis (HD) and 19 continuous ambulatory peritoneal dialysis (CAPD). We can observe that the anatomical status of the heart was dependent upon the time of the treatment. The function of the heart was normal much longer. Structural heart's abnormalities were observed earlier in patients on HD than on CAPD.

[Prevalence of Helicobacter pylori-specific IGG and IGA in children and adolescents with chronic renal failure]

Helicobacter pylori, a bacteria first described in 1984, since that time is linked with chronic gastritis and duodenitis. Dyspeptic symptoms and chronic gastritis are common in patients with chronic renal failure (CRF). The aim of the study was to evaluate of Helicobacter pylori-specific IgG and IgA prevalence in 73 CRF children and possible link of H. pylori infection and dyspeptic symptoms. Anti-H. pylori IgG antibodies were present in 20.5% CRF children (treated conservatively--21%; on CAPD--9%; chronically hemodialysed--29.6%), IgA antibodies was present only in 3 dialysed children (4.1%). Comparing to adult CRF patient, a lower rate of H. pylori infection was observed. No correlation between H. pylori seropositivity and a presence of dyspeptic symptoms was observed. Prevalence of H. pylori antibodies was higher in older CRF children and adolescents.

[Urolithiasis and urinary tract abnormalities in children: own experience]

The study aimed analyzing case histories of 36 children (21 girls and 15 boys), from between 3 weeks and 17 years old, with urinary tract abnormalities, admitted to the Pediatric Nephrology Department for renal stone disease within a 5-year period (1995-1999). Most common clinical manifestations, requiring further urinary tract investigation, were: pain, urinary tract infections caused mainly by Gram-negative bacteria, and erythrocyturia. Most frequent anomalies observed in our patients were those resulting in urinary outlet obstruction. Disturbances in uremic acid and oxalate metabolism were abnormalities we have often found in the examined children. The majority of patients underwent a successful conservative treatment. The obtained results indicate that disorders in the urine flow are main risk factors for crystallization in children with urinary tract abnormalities.

Holographic diffractive collimators based on recording with homocentric diverging beams for diode lasers

A single collimating transmission off-axis blazed surface-relief holographic diffractive element that corrects the ellipticity and the astigmatism of a diode-laser beam was designed. The procedure was applied to a hypothetical laser operating at a wavelength of 633 nm that possesses extremely large astigmatism and relatively small ellipticity together with small diverging angles of the laser beam. The element was recorded with only homocentric diverging beams that had pure spherical wave fronts. Because of the off-axis nature of the element, the aberration of asymmetry had to be corrected. The element was tested in a reciprocal way when the incident wave was a collimated He-Ne laser beam. A diffraction-limited beam was obtained that was as large as approximately half of the designed aperture.

[The fate of children with chronic kidney failure in the course of urinary tract abnormalities]

60 children with chronic renal failure caused by inborn urinary tract abnormalities were examined. It was detected that cysto-ureteral refluxes (65% of causes) were most frequent causes of chronic renal failure. Renal function was estimated in the time of diagnosis of the urinary tract abnormalities and after (between 6 months to 16 years). Renal function was impaired in 37% patients when the urinary tract abnormalities were recognised. Diagnosis of the inborn urinary tract abnormalities was delayed in spite of visible clinical manifestation of disease.

[Evaluation of the urinary tract in children with renal agenesis]

The condition of urinary tract in 24 children with kidney agenesia was estimated. 14 out of 24 children had additionally renal abnormalities or different renal diseases. It was detected that more than 50% of patients developed chronic failure of this single kidney, but renal function of normal single kidney remains many years correct.

[Concentration of selected trace elements in serum and erythrocytes of children with chronic renal failure and am attempt at deficiency correction with animal blood preparation]

The results are presented of studies in 32 children with chronic renal failure treated conservatively in whom the value was evaluated of serum Mg, Zn, and Se concentration, and erythrocyte Mg, and Zn concentration. Among the patients a group of 15 children was isolated whose diet was enriched with the animal blood preparation brown Livex containing among others the studied trace elements. Significant Zn and Mg deficiency was demonstrated in the serum and Mg deficiency in the erythrocytes of the ill children which were effectively corrected after three months of supplementation with the preparation Livex.

[Treatment of anemia with animal blood preparation "Livex" in children with pyelonephritis]

The results are presented of anaemia treatment during pyelonephritis in 20 children with the preparation obtained from animal blood livex. The preparation was administered for eight weeks. After the treatment of a statistically significant rise was observed of haematocrit and haemoglobin concentration. No adverse effects of the preparation were observed.

Size of the unaffected kidney in children with unilateral hydronephrosis

Children with unilateral hydronephrosis, but without evidently decreased excretion of urographic contrast medium, generally had enlargement of the unaffected mate kidney, indicating reduced function of the hydronephrotic kidney.