A-018 Validation of Pericardial Fluid on the Roche Cobas c702 Analyzer: Enhancing Standardization and Efficiency in Clinical Laboratories

Background The accumulation of fluid in the pericardial sac, known as pericardial effusion, can result from a variety of medical conditions such as infections, injuries, autoimmune diseases, cancer, and renal failure. Accurate and precise biomarker analysis of pericardial fluid may be helpful in identifying the underlying causes of fluid accumulation. While pericardiocentesis is performed to relieve cardiac pressure and prevent tamponade, the diagnostic potential of pericardial fluid remains underutilized. The analysis of key biomarkers in pericardial fluid, such as albumin, amylase, blood urea nitrogen, cholesterol, direct bilirubin, lactate, lactate dehydrogenase, total bilirubin, and total protein can provide valuable insights into the etiology of pericardial effusion. However, pericardial fluid is not currently an approved specimen type for any tests available on automated chemistry analyzers. This study aims to validate the analysis of these key analytes to establish their analytical performance following the guideline form The College of American Pathologists (CAP) for body fluid that includes accuracy, precision, analytical measuring range (AMR), reportable range, sensitivity, specificity, interferences and stability. Methods Residual pericardial specimens originally obtained for cytology analysis were used to evaluate the analytical performance of nine biochemical analytes on the Roche Cobas c702 analyzer. The matrix effects of pericardial fluid on the measurement of the nine analytes were assessed by recovery studies. Samples of pericardial fluid containing various concentrations of an analyte was prepared by spiking a pericardial fluid with a known amount of the analyte in a ratio no less than 9:1 (volume of pericardial fluid to volume of the standard solution). Recovery was calculated by the ratio of the measured and the expected concentration of an analyte. Linearity was established using five samples with various concentrations of an analyte spanning the AMR. Intra and inter-assay precision were determined at three levels (L1, L2, and L3) near the clinical decision level, a lower and a higher level, respectively. Intra-assay was determined by testing each level 20 times, while inter-assay was assessed through quadruplicate(4X) analyses over 5 days. Interference studies assessed the effects of hemoglobin (101, 203, 602, and 1213 mg/dL), bilirubin (5.9, 12.2, 20.1, and 33.3 mg/dL), and triglycerides (120, 478, 1142, and 1707 mg/dL) on the measurement of these analytes. Results Recovery studies showed that values were within the acceptable limits (90% to 110%), showcasing reliable performance in pericardial fluid (Figure 1). Precision at various levels meet the acceptance criteria with coefficient of variation (CV) within 10%. Linearity of each analyte demonstrated a slope of >0.998 for all analytes, exhibiting an excellent linear response for all analytes tested. No significant interference was found for all nine analytes except for direct bilirubin at the levels of hemoglobin, bilirubin, and triglycerides used in the study. Hemolysis and icterus interfered with direct bilirubin. Conclusion This validation study provides the evidence that the performance of the albumin, amylase, blood urea nitrogen (BUN), cholesterol, direct bilirubin, lactate, lactate dehydrogenase (LDH), total bilirubin, and total protein assays on the Roche Cobas c702 analyzer are acceptable for pericardial fluid.