Comparative repeatability of pancreatic lipase assays in the commercial and in-house laboratory environments.

BACKGROUND: Sensitivity and specificity for commercial and in-house pancreatic lipase immunoreactivity (cPLI) assays have been reported, but repeatability under routine clinical conditions is unknown. OBJECTIVES: To determine: Coefficient of variation (CV) between replicates of a commercial assay (Spec cPL) and 2 in-house assays (VetScan cPL, Vcheck cPL) under routine conditions. Effects of sample condition or personnel on results. Potential directional bias between assays. ANIMALS: Serum from 12 canine clinical patients. METHODS: Prospective study. Serum Spec cPL, VetScan cPL, and Vcheck cPL (6 aliquots each) were measured, and CVs were calculated, effects of sample condition and personnel were assessed using a linear mixed model, and direction of bias was assessed using least square mean cPLI concentration. RESULTS: Mean %CVs for Spec cPL, VetScan cPL, and Vcheck cPL were 5.5, 17.0, and 23.7%. Three of 6 VetScan cPL samples and 5/9 Vcheck cPL samples had an unacceptably high %CV (>20%). Transportation (Spec cPL) and sample condition or personnel (VetScan cPL, Vcheck cPL) did not affect repeatability. Least square mean cPL was higher for Spec cPL (807.9 µg/L) than for VetScan cPL (558.5 µg/L) or Vcheck cPL (399.8 µg/L). CONCLUSIONS AND CLINICAL IMPORTANCE: For clinical use, the commercial Spec cPL has the highest repeatability, and Vcheck cPL has significantly lower repeatability. Both in-house assays evaluated may provide discrepant categorical results ("pancreatitis" versus "equivocal" versus "not pancreatitis") for the same sample. In-house pancreatic lipase concentrations may be lower than those determined by the Spec cPL assay.