Biochemical analysis of pleural, peritoneal and pericardial effusions

Laboratory investigation of peritoneal fluids: an updated practical approach based on the available evidence

Even though analysis of peritoneal fluids (PF) is often requested to medical laboratories for biochemical and morphological tests, there is still no mutual agreement on what the most appropriate way is to manage PF samples and which tests should be appropriately executed. In this update, we tried to identify the most useful tests for PF analysis to establish best practice indications. We performed a literature review and examined available guidelines to select the most appropriate tests by an evidence-based approach. Accordingly, the basic PF profile should include (1) serum to effusion albumin gradient and (2) automated cell counts with differential analysis. This profile allows to determine the PF nature, differentiating between 'high-albumin gradient' and 'low-albumin gradient' effusions, which helps to identify the pathophysiological process causing the ascites formation. Restricted to specific clinical situations, additional tests can be requested as follows: PF lactate dehydrogenase (LDH) and glucose, to exclude (LDH) or confirm (glucose) secondary bacterial peritonitis; PF total protein, to differentiate ascites of cardiac origin from other causes; PF (pancreatic) amylase, for the identification of pancreatic ascites; PF bilirubin, when a choleperitoneum is suspected; PF triglycerides, in differentiating chylous from pseudochylous ascites and PF creatinine, to detect intraperitoneal urinary leakage.

A Review of Current Practices and Future Trends in Body Fluid Testing

BACKGROUND

Body fluid testing in the clinical chemistry laboratory is a cornerstone in the diagnostic workup of pathological effusions. Laboratorians may not be aware of the preanalytical workflows used in the collection of body fluids though the value is evident whenever processes change or issues arise. The analytical validation requirements can vary depending on the regulations dictated by the laboratories' jurisdiction and accreditor requirements. Much of analytical validation hinges on how useful testing is to clinical care. Usefulness of testing varies with how well established and incorporated the tests and interpretation are in practice guidelines.

CONTENT

Body fluid collections are depicted and described so clinical laboratorians have a basic appreciation of what specimens are submitted to the laboratory for testing. A review of validation requirements by major laboratory accreditation entities is presented. A review of the usefulness and proposed decision limits for common body fluid chemistry analytes is presented. Body fluid tests that show promise and those that are losing (or lost long ago) value are also reviewed.

SUMMARY

The total testing process from collection to result interpretation can be complicated and easily overlooked by the clinical laboratory. This review aims to improve the understanding and awareness of collections, validation, result interpretation, and provide an update on recent trends.

Simplified Light's Criteria and Acute Phase Proteins Reflect Aetiology of Feline Body Cavity Effusions Better than the Traditional Classification Scheme

The traditional veterinary classification (TVC) of effusions based on cell count and total protein (TP) does not adequately reflect the aetiology. Light's criteria (LC) (activity of lactate dehydrogenase [LDH] in the effusion [LDHef], effusion/serum LDH ratio [LDHr], effusion/serum TP ratio [TPr]), serum-effusion albumin gradient (ALBg), acute phase proteins (APPs) [serum amyloid A (SAA), α₁-acid glycoprotein (AGP), haptoglobin] might aid classification. The aim was to evaluate the utility of these parameters except LDHr in differentiating exudates from transudates. Sixty-five cats with effusions (33 peritoneal, 31 pleural, 1 pericardial), with 18 transudates and 47 exudates based on aetiological classification (AC), were included. The sensitivity, specificity and accuracy of several parameters to identify exudates (based on AC) was assessed. APPs were compared between exudates and transudates based on AC and TVC, with receiver operating characteristics analysis identifying the best APP to recognise exudates. Simplified LC (LDHef, TPr) had an accuracy of 79% and TVC of 48%. ALBg had the highest sensitivity (98%) and LDHef the highest specificity (83%) in identifying exudates in cats. All APPs but effusion SAA could differentiate exudates from transudates based on AC (effusion AGP had the largest area under the curve 0.79) but not TVC. All parameters were better than TVC in identifying exudates. The conformity of APPs with AC but not TVC favours the use of AC to classify effusions.

The laboratory investigation of pleural fluids: An update based on the available evidence

Selecting appropriate laboratory tests based on available evidence is central to improve clinical effectiveness and impacting on patient outcome. Although long studied, there is no mutual agreement upon pleural fluid (PF) management in the laboratory context. Given the experienced confusion about the real contribution of laboratory investigations to guide clinical interpretation, in this update, we tried to identify useful tests for the PF analysis, aiming to unravel critical points and to define a common line in requesting modalities and practical management. We performed a careful literature review and a deepened study on available guidelines to finalize an evidence-based test selection, intended for clinicians' use to streamline PF management. The following tests depicted the basic PF profile routinely needed: (1) abbreviated Light's criteria (PF/serum total protein ratio and PF/serum lactate dehydrogenase ratio) and (2) cell count with differential analysis of haematological cells. This profile fulfils the primary goal to determine the PF nature and discriminate between exudative and transudative effusions. In specific circumstances, clinicians may consider additional tests as follows: the albumin serum to PF gradient, which reduces exudate misclassification rate by Light's criteria in patients with cardiac failure assuming diuretics; PF triglycerides, in differentiating chylothorax from pseudochylothorax; PF glucose, for identification of parapneumonic effusions and other causes of effusion, such as rheumatoid arthritis and malignancy; PF pH, in suspected infectious pleuritis and to give indications for pleural drainage; and PF adenosine deaminase, for a rapid detection of tuberculous effusion.

The value of next-generation metagenomic sequencing in pathogen detection of pleural effusions and ascites from children with sepsis

Objective

To investigate the diagnostic value of metagenomic next-generation sequencing (mNGS) using pleural effusion and ascites from children with sepsis.

Methods

In this study, children with sepsis or severe sepsis and appeared pleural or peritoneal effusions were enrolled, of whom the pleural effusions or ascites and blood samples were conducted pathogen detection using both conventional and mNGS methods. The samples were divided into pathogen-consistent and pathogen-inconsistent groups based on the consistency of mNGS results from different sample types, and into exudate and transudate groups based on their pleural effusion and ascites properties. The pathogen positive rates, pathogen spectrum, consistency between different sample types, and clinical diagnosis consistency were compared between mNGS and conventional pathogen tests.

Results

A total of 42 pleural effusions or ascites and 50 other type samples were collected from 32 children. The pathogen positive rate of the mNGS test was significantly higher than that of traditional methods (78.57% vs. 14.29%, P < 0.001) in pleural effusion and ascites samples, with a consistent rate of 66.67% between the two methods. Nearly 78.79% (26/33) of mNGS positive results of the pleural effusions and ascites samples were consistent with clinical evaluation, and 81.82% (27/33) of these positive samples reported 1-3 pathogens. The pathogen-consistent group outperformed the pathogen-inconsistent group in terms of consistency with respect to clinical evaluation (88.46% vs. 57.14%, P = 0.093), while there was no significant difference between the exudate and transudate groups (66.67% vs. 50.00%, P = 0.483).

Conclusion

Compared to conventional methods, mNGS has great advantages in pathogen detection of pleural effusion and ascites samples. Moreover, consistent results of mNGS tests with different sample types provide more reference values in clinical diagnosis.

Myeloperoxidase Levels in Pericardial Fluid Is Independently Associated with Postoperative Atrial Fibrillation after Isolated Coronary Artery Bypass Surgery

BACKGROUND

Postoperative atrial fibrillation (POAF) is the most common complication after surgery for atherosclerotic cardiovascular disease (ASCVD) and leads to extended hospital stays and increased mortality. Myeloperoxidase (MPO) in postoperative pericardial drainage fluid is associated with an increased risk of POAF; however, the correlations between MPO in intraoperative pericardial fluid and POAF remain largely unknown. The aim of the study was to evaluate whether MPO is associated with POAF.

METHODS

A total of 97 patients with no history of atrial arrhythmia who had undergone coronary artery bypass surgery (CABG) were identified. We prospectively measured the levels of MPO in intraoperative pericardial fluid and blood using the human magnetic Luminex assay. Then, the occurrence of atrial fibrillation was continuously observed by postoperative ECG and telemetry strips until discharge.

RESULTS

Our data showed that POAF occurred in 24 of 97 patients (24.74%). MPO levels in blood were higher in the POAF group than the SR group (p = 0.064). Patients with POAF had significantly higher intraoperative pericardial fluid MPO levels than patients who remained in SR (p = 0.021). There was no significant correlation between pericardial fluid MPO levels and blood MPO levels (r = -0.47, p = 0.770). In a multivariable logistic regression model, pericardial fluid MPO levels were significantly associated with a higher risk of POAF (odds ratio = 1.016, 95% confidence interval, 1.001-1.031; p = 0.031).

CONCLUSIONS

Higher intraoperative pericardial fluid MPO levels are linked with POAF in patients undergoing CABG. This finding provides insight into a possible mechanism of MPO in pericardial fluid increase susceptibility to developing POAF in patients undergoing CABG.

Fibrinolysis in Dogs with Intracavitary Effusion: A Review

Simple Summary

In blood vessels there is a balance between clot formation and its dissolution. Fibrinolysis normally allows the breakdown of blood clots during the healing of injured blood vessels. This process is mediated by the activation of a blood enzyme (plasmin) which breaks down a meshed protein (fibrin) which holds blood clots at the site of the vessel injury. In some diseases, the activation of plasmin becomes excessive, leading to bleeding tendencies (hyperfibrinolysis). Under normal conditions, abdominal and thoracic cavities are filled with a small amount of fluid deriving from the blood. The results of recent studies have shown that, in dogs, all types of pathologic intracavitary fluids have an increased fibrinolytic activity. This increased fibrinolytic activity is also present in their blood, in some cases reaching a hyperfibrinolytic state. Hyperfibrinolysis and bleeding tendencies have also been documented in cardiopathic dogs with ascites. The latter result is surprising considering that thrombotic events are commonly documented in humans and cats with some cardiac diseases.

Abstract

Physiologic fibrinolysis is a localized process in which stable fibrin strands are broken down by plasmin in response to thrombosis. Plasmin activation can also take place separately from the coagulation process, resulting in pathologic fibrinolysis. When plasmin activation exceeds the neutralizing capacity of plasmin inhibitors, severe bleeding can potentially take place. Although the processes which regulate coagulation and fibrinolysis in the blood are well known, it is less clear as to what extent the same processes take place in the body cavities and whether they influence systemic hemostasis. The results of the studies herein cited demonstrate that coagulation followed by fibrinogenolytic/fibrinolytic activity takes place in all kinds of canine ascitic and pleural fluids. Moreover, systemic clotting abnormalities suggesting primary fibrinolysis/primary hyperfibrinolysis (i.e., elevated plasma fibrin/fibrinogen degradation products [FDPs] and normal D-dimer concentrations with fibrinogen concentrations ≤ 100 mg/dL or above this cut-off, respectively) occur in dogs with intracavitary effusion. Enhanced fibrinolytic activity in dogs with intracavitary effusion can also be detected using rotational thromboelastometry (ROTEM), although the degree of agreement between ROTEM and FDPs, D-dimer and fibrinogen concentrations is poor. Finally, contrary to the thrombotic events commonly documented in some humans and cats with cardiac diseases, bleeding tendencies due to primary fibrinolysis/primary hyperfibrinolysis have been documented in dogs with cardiogenic ascites.

Comparison of Five Common Analyzers in the Measurement of Chemistry Analytes in an Authentic Cohort of Body Fluid Specimens

OBJECTIVES

Interpretation of body fluid (BF) results is based on published studies and clinical guidelines. The aim of this study is to determine whether the assays from five common commercial vendors produce similar results in BFs for 12 analytes in a BF cohort.

METHODS

BFs (n = 25) and serum (n = 5) were analyzed on five instruments (Roche cobas c501, Ortho 5600, Beckman AU5800 and DXI800, Siemens Vista 1500, and Abbott Architect c8000) to measure albumin, amylase, total bilirubin, cholesterol, creatinine, glucose, lactate dehydrogenase (LDH), lipase, total protein, triglycerides, urea nitrogen, and carcinoembryonic antigen. Deming regression and Bland-Altman analysis were used for method comparison to Roche.

RESULTS

Results were significantly different from Roche for LDH and lipase on Ortho and lipase on Siemens but similar for both BFs and serum. BF differences were larger than serum differences when measuring creatinine, glucose, and urea nitrogen on Ortho and glucose on Siemens.

CONCLUSIONS

Five instruments used to perform BF testing produce results that are not significantly different except for lipase and LDH measurements. Bias of similar magnitude observed in both BF and serum should not affect interpretation. Further investigations into Ortho and Siemens measuring glucose and Ortho measuring creatinine and urea nitrogen are warranted.

Discriminating transudates and exudates in dogs with pleural effusion: diagnostic utility of simplified Light's criteria compared with traditional veterinary classification

OBJECTIVES

To determine whether the simplified Light's criteria (ie, pleural effusion lactate dehydrogenase concentration and serum total protein) can identify the pathophysiology of pleural effusion formation in dogs, and to assess whether these criteria were more accurate than the traditional veterinary classification based on pleural effusion total protein (TPp) and nucleated cell count (TNCCp).

METHODS

This is a cross-sectional study including 100 dogs with pleural effusion. The aetiology of effusion was used to classify the pathophysiology of its formation. Parameters measured included the simplified Light's criteria, TPp and TNCCp. The diagnostic utility of the two methods in classifying pleural effusion formation was evaluated.

RESULTS

Seven transudates due to decreased colloid osmotic pressure, 18 transudates due to increased hydrostatic pressure gradient and 75 exudates were included in the study. The simplified Light's criteria misclassified 2 of 75 exudates (98 per cent overall accuracy). The traditional veterinary classification scheme misclassified 31 of 75 exudates and 12 of 18 increased hydrostatic pressure gradient transudates (57 per cent overall accuracy). The frequency of agreement between the simplified Light's criteria and the traditional veterinary classification with the true nature of the pleural effusion was significantly different (P<0.001).

CLINICAL SIGNIFICANCE

The simplified Light's criteria were highly accurate in discriminating exudates from transudates, while TPp and TNCCp had no diagnostic value in doing so.

Graves' disease inducing a massive cardiac tamponade

A 23-year-old woman was diagnosed with Graves' disease 5 months ago with decompensated thyroid function, for which she is taking thiamazole and propranolol. She developed progressive respiratory dyspnoea [New York Heart Association (NYHA) class III] and frequent palpitations. On emergency admission, the patient was tachypnoeic, hypotensive (77/54 mm Hg) and tachycardic (120 beats per minute), with an oxygen saturation of 94%. She also presented with cold, swollen and shaky extremities, with extended capillary filling time, and a significant reduction in heart sounds. Echocardiogram showed massive pericardial effusion compatible with cardiac tamponade. Pericardiocentesis was performed, with a drainage of 1420 mL serosanguinolent fluid, with prompt haemodynamic recovery. Analysis of the pericardial fluid showed exudates. A diagnosis of pericardial effusion secondary to Graves' disease was determined and corticotherapy, lithium carbonate, cholestyramine and phenobarbital were prescribed. An oral iodine-131 was performed and the patient showed reasonable control of the clinical manifestations of hyperthyroidism. After 3 months, the patient showed no symptoms of hyperthyroidism and a new echocardiogram revealed a significant reduction in pericardial effusion.

Potential hemo-biological identification markers to the left displaced abomasum in dairy cows

Background

Left displaced abomasum (LDA) occurs at high frequency in the early postpartum period and can affect production performance of dairy cows. Clinical diagnosis of LDA is usually done by abdominal auscultation and percussion. The purpose of this study was to explore the potential applicability of blood biomarkers for early warning and diagnosis of LDA in dairy cows.

Results

Twenty early postpartum healthy cows and thirty early postpartum LDA cows of similar parity were used. A receiver operating characteristic curve (ROC) method was used to analyze the sensitivity of hematological biomarkers to LDA including energy balance metabolic biomarkers, liver/kidney function biomarkers, and minerals. A cut-off point was defined for each of the selected hematological biomarkers deemed sensitive markers of LDA. Compared with healthy cows, body condition score (BCS), dry matter intake (DMI) and milk production were lower in LDA cows. Among energy metabolism markers, serum non-esterified fatty acid (NEFA), β-hydroxybutyric acid (BHBA), insulin (INS), and revised quantitative insulin sensitivity check index (RQUICKI) levels were lower while serum glucagon (GC) was greater in LDA cows. Among the liver/kidney function biomarkers, activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transpeptidase (GGT), lactate dehydrogenase (LDH), the ratio of AST/ALT and levels of total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), albumin (ALB), blood urea nitrogen (BUN), creatinine, and total protein (TP) were greater in LDA cows. Among minerals analyzed, serum Cl, Ca, and K were lower in LDA cows. After ROC analysis, it was determined that serum Ca, INS, RQUICKI, ALT, GGT, and creatinine are potential indicators for early warning and diagnosis of LDA for early postpartum dairy cows.

Conclusions

Dairy cows with LDA were under severe negative energy balance (NEB), had signs of liver damage and potentially lower insulin sensitivity. A combination of multi-hematological biomarkers including Ca, INS, RQUICKI, ALT, GGT and creatinine has the potential to help identify cows at risk of LDA in the early postpartum period.

What is the normal composition of pericardial fluid?

Objective

Biochemical and cytological pericardial fluid (PF) analysis is essentially based on the knowledge of pleural fluid composition. The aim of the present study is to identify reference intervals (RIs) for PF according to state-of-art methodological standards.

Methods

We prospectively collected and analysed the PF and venous blood of consecutive subjects undergoing elective open-heart surgery from July 2017 to October 2018. Exclusion criteria for study enrolment were evidence of pericardial diseases at preoperatory workup or at intraoperatory assessment, or any other condition that could affect PF analysis.

Results

The final study sample included 120 patients (median age 69 years, 83 men, 69.1%). The main findings were (1) High levels of proteins, albumin and lactate dehydrogenase (LDH), but not of glucose and cholesterol (2) High cellularity, mainly represented by mesothelial cells. RIs for pericardial biochemistry were: protein content 1.7–4.6 g/dL PF/serum protein ratio 0.29–0.83, albumin 1.19–3.06 g/dL, pericardium-to-serum albumin gradient 0.18–2.37 g/dL, LDH 141–2613 U/L, PF/serum LDH ratio 0.40–2.99, glucose 80–134 mg/dL, total cholesterol 12–69 mg/dL, PF/serum cholesterol ratio 0.07–0.51. RIs for pericardial cells by optic microscopy were: 278–5608 × 106 nucleated cells/L, 40–3790 × 106 mesothelial cells/L, 35–2210 × 106 leucocytes/L, 19–1634 × 106 lymphocytes/L.

Conclusions

PF is rich in nucleated cells, protein, albumin, LDH, at levels consistent with inflammatory exudates in other biological fluids. Physicians should stop to interpret PF as exudate or transudate according to tools not validated for this setting.

Voltammetric analysis for distinguishing portal hypertension-related from malignancy-related ascites: A proof of concept study

Background

Serum-ascites albumin gradient (SAAG) remains the most sensitive and specific marker for the differentiation of ascites due to portal hypertension from ascites due to other causes. SAAG has some limitations and may fail in selected conditions. Voltammetric analysis (VA) has been used for the detection of electroactive species of biological significance and has proven effective for detection infections in biological fluids.

Aims

In this study, we compared the accuracy of voltammetric analysis (VA) with that of SAAG to differentiate ascites due to portal hypertension from that having a different origin.

Methods

80 ascites samples were obtained from patients undergoing paracentesis at the Campus Bio-Medico Hospital of Rome. VA was performed using the BIONOTE device. The ability of VA to discriminate ascitic fluid etiology and biochemical parameters was evaluated using Partial Least Square Discriminant Analysis (PLS-DA), with ten-fold cross-validations.

Results

Mean age was 68.6 years (SD 12.5), 58% were male. Ascites was secondary to only portal hypertension in 72.5% of cases (58 subjects) and it was secondary to a baseline neoplastic disease in 27.5% of cases (22 subjects). Compared to SAAG≥1.1, e-tongue predicted ascites from portal hypertension with a better accuracy (92.5% Vs 87.5%); sensitivity (98.3% Vs 94.8%); specificity (77.3% Vs 68.2%); predictive values (PPV 91.9% Vs 88.7% and NPV 94.4% Vs 83.3%). VA correctly classified ascites etiology in 57/58 (98.2%) of cases with portal hypertension and in 17/22 (77.2%) of cases with malignancy. Instead, VA showed poor predictive capacities towards total white blood count and polymorphonuclear cell count.

Conclusions

According to this proof of concept study, VA qualifies as a promising low-cost and easy method to discriminate between ascites secondary to portal hypertension and ascites due to malignancy.

Laboratory testing of extravascular body fluids: National recommendations on behalf of the Croatian Society of Medical Biochemistry and Laboratory Medicine. Part I - Serous fluids

Extravascular body fluids (EBF) analysis can provide useful information in the differential diagnosis of conditions that caused their accumulation. Their unique nature and particular requirements accompanying EBF analysis need to be recognized in order to minimize possible negative implications on patient safety. This recommendation was prepared by the members of the Working group for extravascular body fluid samples (WG EBFS). It is designed to address the total testing process and clinical significance of tests used in EBF analysis. The recommendation begins with a chapter addressing validation of methods used in EBF analysis, and continues with specific recommendations for serous fluids analysis. It is organized in sections referring to the preanalytical, analytical and postanalytical phase with specific recommendations presented in boxes. Its main goal is to assist in the attainment of national harmonization of serous fluid analysis and ultimately improve patient safety and healthcare outcomes. This recommendation is intended to all laboratory professionals performing EBF analysis and healthcare professionals involved in EBF collection and processing. Cytological and microbiological evaluations of EBF are beyond the scope of this document.

Body Fluid Testing at John F. Kennedy Medical Center in Liberia

OBJECTIVES

To apply a simple method to validate testing for albumin, glucose, lactate dehydrogenase (LDH) and total protein (TP) in peritoneal, pleural, and cerebrospinal fluids (CSF) at a hospital in Liberia.

METHODS

Serum and body fluid specimens were mixed to create 100% serum and 25%, 50%, 75%, and 100% fluid tubes, which were tested on a Biotecnica BT3500. Differences less than 10% between calculated and measured concentrations were considered acceptable.

RESULTS

The means (confidence intervals) of the percent differences were: albumin/peritoneal 12.8 (6.0-19.7), albumin/pleural 2.8 (1.3-4.2), albumin/CSF 4.8 (2.2-7.5), glucose/peritoneal 4.0 (1.9-6.0), glucose/pleural 4.4 (3.1-5.7), glucose/CSF 2.9 (1.8-4.0), LDH/peritoneal 9.5 (6.3-12.7), LDH/pleural 9.5 (5.4-13.6), LDH/CSF 9.2 (5.2-13.3), TP/peritoneal 7.6 (3.8-11.4), TP/pleural 3.8 (1.5-6.2), and TP/CSF 4.5 (1.0-8.1).

CONCLUSIONS

All mean differences except for one were less than 10%, allowing for the adoption of clinical testing. The mixing study is a low-cost method for quality-assured testing that can be performed by resource-limited laboratories.

Computed tomography attenuation value for the characterization of pleural effusions in dogs: A cross-sectional study in 58 dogs

CT attenuation value can help to differentiate exudate from transudate in people. The aim of this cross-sectional study was to assess the utility of CT in characterizing pleural effusions based on attenuation values in a population of dogs having CT and diagnostic thoracentesis within 48 h of each other. The CT attenuation values were determined using four circular, same size, regions of interest (ROIs) placed on the same CT slice with the greatest quantity of fluid. Values of each ROI were recorded and the mean of the four ROIs mean values (mean of the means) was calculated and considered as the CT attenuation value of that patient. The final population included 23 proper inflammatory exudates, 15 chylous effusions, 12 hemorrhagic effusions and 8 transudates. The median of 'mean of the means' values were: exudate 19.22 HU (8.23 to 37.66 HU); chylous effusion 10.26 HU (-0.90 to 15.37); hemorrhagic effusion 31.65 HU (18.10 to 54.97), and transudate 11.20 HU, (-2.52 to 16.59). CT accurately differentiated hemorrhagic from chylous effusion (AUC 1.0, P < 0.0001) and hemorrhagic effusion from transudate (AUC 1.0, P < 0.0001); CT-values allowed good accuracy in distinguishing exudates from transudates [AUC 0.87 (95%, CI: 0.74-1.0; P < 0.0001)]. HU attenuation values did not accurately differentiate between transudates and chylous effusion. A cutoff value of 34.68 HU (sensitivity of 96% and specificity of 95%) discriminated between exudates and hemorrhagic effusions. CT-value <12.15 HU had a sensitivity of 94% and specificity of 78% for identify transudate or chylous effusion.

Hemostatic findings of pleural fluid in dogs and the association between pleural effusions and primary hyperfibrino(geno)lysis: A cohort study of 99 dogs

The primary objective of this study was to determine if activation of coagulation and fibrinolysis occurs in canine pleural effusions. Thirty-three dogs with pleural effusions of different origin were studied. Pleural effusion fibrinogen concentrations were significantly lower, while pleural fibrin-fibrinogen degradation products (FDPs) and D-dimer concentrations were significantly higher than those in plasma (P < 0.001 for all comparisons). These results show that, in canine pleural fluids, there is evidence of coagulation activation and fibrinolysis. The secondary aims of the current study were to determine if primary hyperfibrinolysis ([PHF] i.e., elevated plasma FDPs with a normal D-dimer concentrations), occurs in dogs with pleural effusion, and whether the presence of a concurrent inflammatory process may have activated the hemostatic cascade, with its intrinsically linked secondary hyperfibrinolysis, masking the concurrent PHF. The previously 33 selected dogs with pleural effusion (group 1) were compared to two control groups of 33 healthy (group 2) and 33 sick dogs without pleural effusion (group 3). Serum fibrinogen, FDPs, D-dimer, C-reactive protein (CRP), fibrinogen/CRP ratio, and frequency of PHF were determined. Fibrinogen, FDPs, D-dimer and CRP concentrations in group 1 were significantly increased compared to group 2 (P < 0.001 for all comparisons). FDPs and CRP concentrations in group 1 were also significantly increased compared to group 3 (P = 0.001 and P < 0.001, respectively). The fibrinogen/CRP ratio was significantly decreased in group 1 compared to groups 2 and 3 (P < 0.001 for both comparison). The frequency of PHF was significantly higher in group 1 compared to groups 2 (P = 0.004), but not compared to group 3. These results support the hypothesis that PHF occurs significantly more often in dogs with pleural effusion compared to healthy dogs. Nevertheless, the decrease in the fibrinogen/CRP ratio in group 1 compared to group 3, considering the higher FDPs and similar D-dimer concentrations, would suggest that PHF is also more frequent in dogs with pleural effusion compared to sick control dogs, and that this phenomenon is hidden due to concurrent secondary hyperfibrinolysis.

A fractionation approach applying chelating magnetic nanoparticles to characterize pericardial fluid's proteome

Owing to their close proximity, pericardial fluid (PF)'s proteome may mirror the pathophysiological status of the heart. Despite this diagnosis potential, the knowledge of PF's proteome is scarce. Large amounts of albumin hamper the characterization of the least abundant proteins in PF. Aiming to expand PF's proteome and to validate the technique for future applications, we have fractionated and characterized the PF, using N-(trimethoxysilylpropyl)ethylenediamine triacetic acid (EDTA)-functionalized magnetic nanoparticles (NPs@EDTA) followed by a GeLC-MS/MS approach. Similarly to an albumin-depletion kit, NPs@EDTA-based fractionation was efficient in removing albumin. Both methods displayed comparable inter-individual variability, but NPs@EDTA outperformed the former with regard to the protein dynamic range as well as to the monitoring of biological processes. Overall, 565 proteins were identified, of which 297 (>50%) have never been assigned to PF. Moreover, owing to this method's good proteome reproducibility, affordability, rapid automation and high binding ability of NP@EDTA, it bears a great potential towards future clinical application.

Hemostatic Findings in Ascitic Fluid: A Cross-Sectional Study in 70 Dogs

BACKGROUND

Ascitic fluids of horses and humans have fibrinolytic activity, independent of the underlying mechanism of fluid formation.

OBJECTIVE

To determine whether coagulation and fibrinogenolytic/fibrinolytic activity (ie, low fibrinogen and increased fibrin-fibrinogen degradation products [FDPs], D-dimer, or both) occur in all types of ascitic fluid in dogs.

ANIMALS

A total of 70 client-owned dogs with ascites.

METHODS

In this cross-sectional study, dogs were categorized based on the pathophysiology of fluid formation into 4 groups: transudates due to decreased osmotic pressure, transudates due to increased hydrostatic pressure, exudates, and hemorrhagic ascites. Fibrinogen, FDPs, and D-dimer concentrations were measured and then compared in both ascitic fluid and plasma.

RESULTS

Ten dogs had transudates due to decreased colloid osmotic pressure, 18 had transudates due to increased hydrostatic pressure, 13 had exudates, and 29 had hemorrhagic ascites. Ascitic fibrinogen concentrations (n = 70) were significantly lower (median = 59 mg/dL; range: 59-122 mg/dL) than those in the plasma (median = 168 mg/dL, range: 59-879 mg/dL; P < .0001). Ascitic FDPs concentrations (n = 70) were significantly higher (<5 μg/mL: 3/70 dogs, ≥5 to <20 μg/mL: 11/70 dogs, ≥20 μg/mL: 56/70 dogs) than those in the plasma (<5 μg/mL: 17/70 dogs, ≥5 to <20 μg/mL: 28/70 dogs, ≥20 μg/mL: 25/70 dogs; P < .0001). Ascitic D-dimer concentrations (n = 70) were significantly higher (median = 3.98 μg/mL, range: 0.02-9.19) than those in the plasma (median = 0.11 μg/mL, range: 0.01-4.08; P < .0001). Analysis of the data for each of the 4 different types of ascites showed similar results to those of all the data analyzed together.

CONCLUSIONS AND CLINICAL IMPORTANCE

Ascitic fluid of dogs has evidence of coagulation activation and fibrinogenolytic/fibrinolytic activity and that this phenomenon occurs independent of the underlying mechanism that leads to the formation of ascites.

Laboratory testing of extravascular body fluids in Croatia: a survey of the Working group for extravascular body fluids of the Croatian Society of Medical Biochemistry and Laboratory Medicine

INTRODUCTION

We hypothesized that extravascular body fluid (EBF) analysis in Croatia is not harmonized and aimed to investigate preanalytical, analytical and postanalytical procedures used in EBF analysis in order to identify key aspects that should be addressed in future harmonization attempts.

MATERIALS AND METHODS

An anonymous online survey created to explore laboratory testing of EBF was sent to secondary, tertiary and private health care Medical Biochemistry Laboratories (MBLs) in Croatia. Statements were designed to address preanalytical, analytical and postanalytical procedures of cerebrospinal, pleural, peritoneal (ascites), pericardial, seminal, synovial, amniotic fluid and sweat. Participants were asked to declare the strength of agreement with proposed statements using a Likert scale. Mean scores for corresponding separate statements divided according to health care setting were calculated and compared.

RESULTS

The survey response rate was 0.64 (58 / 90). None of the participating private MBLs declared to analyse EBF. We report a mean score of 3.45 obtained for all statements evaluated. Deviations from desirable procedures were demonstrated in all EBF testing phases. Minor differences in procedures used for EBF analysis comparing secondary and tertiary health care MBLs were found. The lowest scores were obtained for statements regarding quality control procedures in EBF analysis, participation in proficiency testing programmes and provision of interpretative comments on EBF's test reports.

CONCLUSIONS

Although good laboratory EBF practice is present in Croatia, procedures for EBF analysis should be further harmonized to improve the quality of EBF testing and patient safety.

Lipidomic Profiling of Lung Pleural Effusion Identifies Unique Metabotype for EGFR Mutants in Non-Small Cell Lung Cancer

Cytology and histology forms the cornerstone for the diagnosis of non-small cell lung cancer (NSCLC) but obtaining sufficient tumour cells or tissue biopsies for these tests remains a challenge. We investigate the lipidome of lung pleural effusion (PE) for unique metabolic signatures to discriminate benign versus malignant PE and EGFR versus non-EGFR malignant subgroups to identify novel diagnostic markers that is independent of tumour cell availability. Using liquid chromatography mass spectrometry, we profiled the lipidomes of the PE of 30 benign and 41 malignant cases with or without EGFR mutation. Unsupervised principal component analysis revealed distinctive differences between the lipidomes of benign and malignant PE as well as between EGFR mutants and non-EGFR mutants. Docosapentaenoic acid and Docosahexaenoic acid gave superior sensitivity and specificity for detecting NSCLC when used singly. Additionally, several 20- and 22- carbon polyunsaturated fatty acids and phospholipid species were significantly elevated in the EGFR mutants compared to non-EGFR mutants. A 7-lipid panel showed great promise in the stratification of EGFR from non-EGFR malignant PE. Our data revealed novel lipid candidate markers in the non-cellular fraction of PE that holds potential to aid the diagnosis of benign, EGFR mutation positive and negative NSCLC.

New Biochemical Parameters in the Differential Diagnosis of Ascitic Fluids

BACKGROUND

In the cases of ascitis, it is essential to determine their origin using the parameters obtained by the cytological and biochemical examinations. The aim of this study was to evaluate the usefulness of different biochemical markers and the number of cells in the differential diagnosis of ascitic fluid (AF).

METHODS

One hundred ninety-one cases of AF were studied, who were admitted to the hospital from January 01, 2009 to December 31, 2014. One hundred fifty-two of them were included in the analysis, and the remaining 39 were excluded because they had more than one associated pathology, clotted or hemolyzed.

RESULTS

The more frequent etiologies of AF were the cirrhosis (29%), the infections (22%) and the neoplasies (19%). Other pathologies reached 16%. Cutoff > 300 cells/mm³ detected the 78% of exudates. The AF/serum (S) of aspartate aminotransferase (AST) (> 0.5), lactate dehydrogenase (LDH) (> 0.6), proteins (PT) (> 0.5), cholesterol (COL) (> 0.4), and alanine aminotransferase (ALT) (> 0.5) correctly detected 80%, 78%, 72%, 70% and 70% of the exudates, respectively.

CONCLUSION

We proposed the utilization of a new cutoff of cellular counting, major of 300/mm³, since it would allow improving the detection of exudate ascites, without including the transudate ascites. AST AF/serum ratio (AF/S) showed the major usefulness in the differentiation and characterization of AF; LDH, proteins, cholesterol and ALT might be also acceptable in the above mentioned differentiation. The serum-ascites albumin gradient (SAAG) turned out to be a good marker of portal hypertension associated with cirrhotic processes. Creatine kinase (CK), alkaline phosphatase (ALP), amylase (AMI), total bilirubin (TB), triglycerides (TG) and glucose (GLU) did not allow differentiating exudates from transudates.

Diagnostic value of the biochemical tests in patients with purulent pericarditis

Objectives: Purulent pericarditis is a collection of purulent effusion in the pericardial space. It has become a rare entity with the increased availability and use of antibiotics. In contrast to pleural empyema, there are few data regarding the biochemical parameters of purulent pericardial effusion to aid diagnosis. Therefore, in this study, we have evaluated the diagnostic utility of biochemical tests in patients with purulent pericarditis.

Methods: Between September 2004 and September 2012, we treated fifteen children with purulent pericarditis and tamponade. There were 8 boys and 7 girls, ranging in age from 8 months to 14 years, with a mean age of 5.3 ± 3.2 years. Echocardiographic diagnosis of cardiac tamponade was made in all patients. All patients underwent immediate surgical drainage due to cardiac tamponade. The diagnosis of purulent pericarditis was supported by biochemical tests. Anterior mini-thoracotomy or subxiphoid approach was performed for surgical drainage.

Results: The most common clinical findings were tamponade, hepatomegaly, tachycardia, fever refractory antibiotic therapy, dyspnea, tachypnea, cough, and increased jugular venous pressure. Central venous pressure decreased and arterial tension increased immediately after the evacuation of purulent effusion during operation in all patients. The pericardial effusion had high lactic dehydrogenase, and low glucose concentration, confirming purulent pericarditis. Also, pH (mean± SD) was 7.01 ± 0.06. The culture of pericardial effusions and blood samples were negative.

Conclusion: Biochemical tests are useful guideline when assessing the pericardial effusions. However, these tests should be interpreted with the clinical and operative findings.

Pleural, peritoneal and pericardial effusions - a biochemical approach

The pathological accumulation of serous fluids in the pleural, peritoneal and pericardial space occurs in a variety of conditions. Since patient management depends on right and timely diagnosis, biochemical analysis of extravascular body fluids is considered a valuable tool in the patient management process. The biochemical evaluation of serous fluids includes the determination of gross appearance, differentiation of transudative from exudative effusions and additional specific biochemical testing to assess the effusion etiology. This article summarized data from the most relevant literature concerning practice with special emphasis on usefulness of biochemical tests used for the investigation of pleural, peritoneal and pericardial effusions. Additionally, preanalytical issues concerning serous fluid analysis were addressed and recommendations concerning acceptable analytical practice in serous fluid analysis were presented.

Acute-phase proteins, oxidative stress and enzyme activities of blood serum and peritoneal fluid in cattle with abomasal displacement

BACKGROUND

Blood serum and peritoneal fluid acute-phase proteins, oxidative stress indicators, and some enzymes could be used for evaluation of abomasal tissue damage because of displacement in displaced abomasum (DA) cases.

OBJECTIVES

The aim of this study was to investigate the concentrations of acute-phase proteins, oxidative stress indicators, and activities of enzymes in blood serum and peritoneal fluid in cattle with right displaced abomasum (RDA) and left displaced abomasum (LDA) and in healthy cows.

ANIMALS

A total of 60 Holstein Friesian cows in early lactation were used, 31 with left and 9 with right displaced abomasum without volvulus diagnosis and no other postpartum disease, and 20 healthy cows as a control.

MATERIALS AND METHODS

DA diagnosis in dairy cows consisted of physical examination, laboratory, and specific DA tests. Acute-phase proteins, oxidative stress indicators, and enzyme activities were measured in blood serum and peritoneal fluid.

RESULTS

In the RDA group, serum haptoglobin (HPG), serum amyloid A (SAA), malondialdehyde (MDA), adenosine deaminase (ADA), myeleperoxidase (MPO), aspartate aminotransferase (AST), creatine kinase (CK, creatine kinase-MB (CK-MB), and gamma-glutamyl transferase (GGT) activity increased significantly, and serum HPG, MDA, ADA, and AST concentrations increased significantly in the LDA group (P < .05). Peritoneal fluid HPG, MDA, ADA, MPO, ALP, GGT, and LDH concentrations increased significantly, whereas NO concentrations reduced significantly in the RDA group, and HPG, MDA, ADA, and TP concentrations increased significantly, whereas concentrations of NO reduced significantly in the LDA group (P < .05).

CONCLUSIONS AND CLINICAL IMPORTANCE

There are acute-phase responses, oxidative stress, and abomasal tissue damage because of displacement in DA cases. Especially, HPG, MDA, ADA, and MPO concentrations can provide specific information to help in understanding these changes.

Metabonomic classification and detection of small molecule biomarkers of malignant pleural effusions

To date, most research has been focused on the benign molecules in pleural effusions, and diagnosis of malignant ones still remains challenging. In the present study, targeting the small molecules as potential biomarkers to predict the malignancy of the effusions, the metabolic profiles of 81 clinical pleural effusions (41 malignant effusions from lung cancer and 40 benign ones) were investigated through a NMR-based metabonomic approach. In (1)H NMR analysis, a total of ten small molecules in the effusions were simultaneously determined. Significantly higher mean values of valine, lactate, and alanine and markedly lower signal intensities of acetoacetate, trimethylamine-N-oxide, and α- and β-glucose were observed in malignant pleural effusions compared with those in benign ones. DFA modeling of NMR spectra subjected to a validation allowed the malignant effusions to be discriminated from benign ones in both training and validation groups. Currently, the conventional clinical analyses on chemical constituents in effusions could not provide a reliable prediction of malignancy of the effusions; the present results revealed that the small molecules might serve as useful biomarkers for diagnosis of the effusions, and the present NMR-based metabonomic approach provided a valuable potential to rapidly and sensitively predict the malignancy of the pleural effusions.

Getting the most from pleural fluid analysis

Virtually, every pulmonary disease and most non-pulmonary diseases may be associated with a pleural effusion. The presence of a pleural effusion allows the clinician to 'diagnose' or narrow the differential diagnosis and aetiology of the fluid collection. However, pleural fluid analysis (PFA) in isolation rarely provides a definitive diagnosis. This review discusses the rationale for evaluating patients with a pleural effusion. If the clinician obtains a detailed history, performs a comprehensive physical examination, reviews pertinent blood tests, and evaluates the chest imaging findings prior to thoracentesis, there should be a high likelihood of establishing a firm clinical diagnosis based on the appropriate PFA. This manuscript reviews the clinical presentation, chest imaging findings, duration and natural course of specific pleural effusions to help narrow the range of pre-thoracentesis diagnoses. A diagnosis of transudative effusion confirms an imbalance in hydrostatic and oncotic pressures, normal pleura and a limited differential diagnosis, which is typically apparent from the clinical presentation. Exudates are the result of infections, malignancies, inflammation, impaired lymphatic drainage or the effects of drugs, and pose a greater diagnostic challenge. The differential diagnosis for a pleural exudate can be narrowed if LDH levels exceed 1000 IU/L, the proportion of lymphocytes is ≥80%, pleural fluid pH is <7.30 or there is pleural eosinophilia of >10%.

Vascular endothelial growth factor in malignant and benign pericardial effusion

BACKGROUND

The pathogenetic role of vascular endothelial growth factor (VEGF) in malignant pericardial effusion and diagnostic value of pericardial VEGF levels to discriminate malignant from benign pericardial effusions are uncertain.

HYPOTHESIS

We hypothesized that pericardial VEGF levels would be higher in malignant than benign pericardial effusion and that VEGF would be a useful marker for the diagnosis of malignant pericardial effusion.

METHODS

Using an enzyme-linked immunosorbent assay, we assessed pericardial and serum VEGF levels in patients with malignant pericardial effusion (n = 19), in patients with nonmalignant pericardial effusion (n = 30), and for control, in patients without pericardial disease (n = 26).

RESULTS

Vascular endothelial growth factor pericardial levels in malignant pericardial effusion (13 593.8 ± 22 410.24 pg/mL) were significantly higher compared with VEGF in nonmalignant effusion (610.63 ± 1289.08 pg/mL; P = 0.001) and pericardial fluid (5.5 ± 15.97 pg/mL; P < 0.001). In serum, VEGF was significantly higher in patients with nonmalignant pericardial effusion (188.3 ± 240.35 pg/mL) compared with patients with malignant pericardial effusion (67.52 ± 125.77 pg/mL; P = 0.024) and coronary artery disease patients (29.13 ± 76.26 pg/mL; P < 0.001). Pericardial VEGF levels were significantly higher than matched serum levels only in patients with malignant pericardial effusion (P = 0.023). Pericardial VEGF levels ≥2385 pg/mL had 75% sensitivity and 90% specificity for the recognition of malignant pericardial effusion in patients with breast or lung cancer.

CONCLUSIONS

Vascular endothelial growth factor levels in pericardial effusion are markedly elevated in patients with malignant pericardial effusion, indicating abundant local release within the pericardial cavity. It is thus possible that VEGF participates in the pathogenesis of malignant pericardial effusion. Measurement of VEGF in pericardial effusion offers potential as a diagnostic tool to discriminate malignant from benign effusions in patients with breast or lung cancer.

Development of a new microtiter plate format for clinically relevant assays

A new format for the microtiter plate-based assays was proposed. The novelty involves the use of disk-shaped inserts for immobilization of biological and chemical reagents. The internal opening of the disks allows measurements of the reactions by standard microtiter plate readers without any additional steps involving liquid handling. Ideally the plate end-users just have to add the sample and take the measurement without any need of multiple reagent additions or transfer of the liquid to a different plate. The novel assay format also allows handling of reagents which are not soluble in an aqueous environment. As a proof of concept we describe here several model reactions which are compatible with microtiter plate format, such as monitoring enzymatic reactions catalyzed by glucose oxidase (GOx) and urease, measurements of proteins by BCA assay, analysis of pH, and concentration of antioxidants. The "mix and match" approach in the disk-shape format allows multiplexing and could be particularly useful for high throughput screening. One of the potential application areas for this novel assay format could be in a multianalyte system for measurement of clinically relevant analytes in primary care.

Osteoprotegerin (OPG) and TNF-related apoptosis-inducing ligand (TRAIL) levels in malignant and benign pericardial effusions

OBJECTIVES

Osteoprotegerin (OPG) is a regulator of bone and vascular homeostasis and acts as a decoy receptor for proapoptotic TNF-related apoptosis-inducing ligand (TRAIL).

DESIGN AND METHODS

We assessed pericardial and serum levels of OPG and TRAIL in pericardial effusions (PE) of malignant (mPE, n=24) or non-malignant (nPE, n=34) origin, and in pericardial fluid (PF, n=25) of coronary artery disease (CAD) patients by ELISA.

RESULTS

OPG was at least 5 fold higher in PE or PF compared to serum, with a significantly higher ratio of pericardial to serum OPG in patients with mPE or nPE compared to PF (mPE vs. PF, p=0.011; nPE vs. PF, p<0.001). TRAIL was only detectable in mPE and PF. Logistic regression analysis revealed that a high ratio of pericardial to serum OPG and high TRAIL in PE were the best variable combination to predict malignancy of PE.

CONCLUSIONS

Pericardial and systemic OPG or TRAIL are potential diagnostic tools to discriminate between malignant or benign PE.

Evaluation of cytologic and biochemical variables in blood, plasma, and peritoneal fluid from calves before and after umbilical herniorrhaphy

OBJECTIVE

To establish reference intervals for cytologic and biochemical variables in peritoneal fluid, whole blood, and plasma in calves with congenital umbilical hernias (CUHs) before and after herniorrhaphy and to assess whether those variables in calves with CUHs were altered, compared with findings in clinically normal calves.

ANIMALS

20 Holstein calves with or without a CUH. Procedures-10 calves with CUHs underwent herniorrhaphy. Blood and peritoneal fluid samples from all 20 calves were collected for cytologic and biochemical analyses on days 0 (before surgery), 1, 3, 5, 7, and 15. Data from the 2 groups were compared.

RESULTS

Reference intervals for the variables of interest were established for each group. Before surgery, calves with CUHs had significantly greater plasma total protein concentration and creatine kinase (CK) and aspartate aminotransferase activities and peritoneal fluid specific gravity values, compared with values for calves without CUHs. At various time points after surgery, peritoneal fluid total protein concentration; fibrinogen concentration; nucleated cell, polymorphonuclear cell, and lymphocyte counts; specific gravity; and lactate dehydrogenase, aspartate aminotransferase, and CK activities in calves with CUHs were significantly different from values in calves without CUHs. Some plasma and blood variables (eg, total protein concentration, neutrophil count, and CK activity) were significantly different between the 2 groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Values of certain cytologic and biochemical variables in peritoneal fluid, blood, and plasma were different between calves with and without CUHs. Thus, determination of reference intervals for these variables is important for interpreting diagnostic test results in calves with CUHs.

Tumor microenvironment: What can effusions teach us?

Malignant effusions, which are composed of malignant pleural and peritoneal fluid, are an unusual manifestation of cancer and frequently portend a poor prognosis. Neoplastic cells that disseminate into cavities containing effusions are highly metastatic and possess a strong autonomous proliferative drive while concurrently being stimulatory of exudative effusions. Most effusions will respond to transient therapeutic intervention, including the obliteration of potential space via pleurodesis. Cure, however, is rare, thus making effusions a biologically, biochemically, and clinically important topic of study. The local microenvironment that supports malignant growth, invasion, and dissemination of the solid primary tumor into the vasculature is composed of activated stroma that includes scaffolding consisting of materials that promote the tumor function, and vascular structures to provide conduits for travel and nutrient delivery. Less is understood about the tumor-cell microenvironment in malignant effusions. The fluid nature of such a microenvironment when compared with the solid primary tumor may have significant implications for disease dissemination and progression. Dissecting the signaling activity and components of such microenvironments will improve our understanding and ultimately our ability to provide better patient care.