Importance of standardization of lipase assays by using appropriate calibrators
Lessinger, J.M.; Dourson, J.L.; Férard, G.
Clinical Chemistry 42(12): 1979-1983
1996
ISSN/ISBN: 0009-9147 PMID: 8969636 Document Number: 462218
Comparability of lipase catalytic activities was poor when lipase was determined in 50 patients' specimens by a turbidimetric (Boehringer) and a colorimetric (Sigma) assay. Mean values of results differed by a ratio of 2.39. Optimal common conditions were defined for the titration of lipase activity in two commercial calibrators and in a home-purified preparation of human pancreatic lipase (HPL). When using these titers for each calibrator, comparability was greatly improved (ratio = 1.25). This result indicates that a significant part of between-method discrepancy is due to the lack of a reference method for the titration of lipase calibrators. Intermethod behavior of each material was compared with that of patients' specimens. By using HPL as calibrator, comparability was still dramatically improved (ratio = 1.01). This study shows the importance of the validation of a material for defined routine measurement procedures, before its use as calibrator.