Evaluation of the hemolysis threshold for the measurement of serum lipase on Roche Cobas systems

Evaluation of the hemolysis threshold for the measurement of serum lipase on Roche Cobas systemsL ipase is a glycoprotein that reduces triglycerides and diglycerides to free fatty acids and glycerol by catalyzing the hydrolysis of ester bonds [1].Lipases are primarily present in pancreatic secretions but can be found in several tissues, including hepatic lipase in the liver, hormone-sensitive lipases in adipocytes, lipoprotein lipase in endothelial cells, and pancreatic lipase in the small intestine [2].Clinically, a lipase test may be used to help diagnose disorders of the pancreas, most often acute pancreatitis.Other pathologies can cause an increase in blood lipase levels, such as pancreatic cancer, gallbladder issues, chronic kidney disease, intestinal problems, cancer of a salivary gland, peptic ulcer disease, primary biliary cirrhosis, and certain drugs [3].The quantitative determination of lipase in human serum and plasma on the Roche Cobas c system is based on the enzymatic hydrolysis of 1,2-O-dilauryl-rac-glycero-3-glutaric acid-(6-methylresorufin) ester, followed by monitoring the production of resorufin, measured photometrically between 570 and 583 nm.The intensity of the red color developed is directly proportional to lipase activity.Hemolysis involves the release of hemoglobin into the extracellular compartment [4].Oxyhemoglobin and deoxyhemoglobin have maximum absorption at 415 nm, with a detection range between 320 and 450 nm and 540 and 589 nm, respectively [5].Thus, Objectives: Following the release of an informational bulletin, Roche Diagnostics adopted a more restrictive hemolysis index (100 HI) for the release of serum lipase results on all Cobas systems.This study aimed to evaluate the interference threshold for serum lipase hemolysis on Cobas C501/311/701/Integra 400 systems using a total allowable error set by the Royal College of Pathologists of Australasia (RCPA).Methods: To assess the influence of hemolysis on lipase, the parameter was quantified in serum pools spiked with escalating concentrations of a hemolysis interferent.The lipase assay was performed using the colorimetric lipase method (LIPC), and the HI was determined by absorbance measurements of diluted samples in accordance with the system protocol.Results: The Cobas Integra 400 and Cobas C311 showed the greatest interference of lipase with hemolysis (300 HI).The Cobas C501 and C701 demonstrated less sensitivity to hemolysis (1300 HI). Conclusion:The results of this study demonstrate that interference limits may vary between different Roche systems, even when the same reagent is used.Our study indicated that the lipase hemolysis threshold (100 HI) currently set by the manufacturer was excessively restrictive.This finding highlights the necessity of verifying manufacturers' information bulletins to provide better medical care.