Perkin M. H. Chan¹, Christopher J. Perkins¹, Rishikesh Pardeshi¹, Kyle-Peter Wollbrandt¹, Catherine Lynch¹, Andrew C. Carter¹

¹Melbourne Pathology, Collingwood

Introduction: At Melbourne Pathology, lipase is measured using the Roche Diagnostics cobas c701 enzymatic colorimetric assay. In 2024, Roche Diagnostics released a bulletin indicating a change in the threshold for significant interference from haemolysis, and revision of the Haemolysis index (H-index) from 620 µmol/L to 62 µmol/L¹. Our laboratory decided to investigate this change.

Method: Low and high lipase level serum pools were spiked with haemolysate to achieve target H-index values. All spiked samples were measured using the same reagent pack on the same day. Data analysis was conducted using Microsoft Excel Analysis ToolPak.

Results & Discussion: For the Roche Diagnostics cobas c701 lipase colorimetric assay, positive H-index concentration-dependent interference in lipase measurement is observed. The newly established H-index limit of 62 µmol/L¹ indicates where haemolysis interference exceeds the RCPAQAP Chemical Pathology Analytical Performance Specifications for lipase². Regression analysis revealed a linear correlation, showing that the erroneous proportion of measured lipase is equal to 0.0049 times the H-index. To prevent misinformed clinical decisions due to falsely elevated lipase concentrations from haemolysis, our laboratory will comment on results exceeding this limit, and provide a ‘corrected lipase’, derived from the aforementioned linear relationship.

References:

1. Roche Diagnostics. Lipase [Method Sheet] [Internet]. 2024 [cited 2024 Oct 8]. Available from: https://elabdoc-prod.roche.com/eLD/api/downloads/1d4a0673-d07c-ef11-2b91-005056a71a5d?countryIsoCode=XG 

2. RCPAQAP. Chemical pathology analytical performance specifications [Internet]. 2024 [cited 2024 Oct 8]. Available from: https://rcpaqap.com.au/resources/chemical-pathology-analytical-performance-specifications/  

Statement of originality: I certify that the intellectual content of this abstract and associated research project is the original idea and work of the listed co-authors and myself.