Evaluation of commercial enzyme reagent kits by use of a semiautomated chemistry analyzer.

The overall performances of several enzyme reagent kits for alkaline phosphatase, creatine kinase, lactic dehydrogenase, and aspartate aminotransferase were evaluated using an ABA-100 Bichromatic Analyzer. Interassay precision using this instrument with commercial reagents compared well with published data for similar analyses performed at university hospitals and referral laboratories. Significantly poorer precision with lower limits of linearity was observed when reagents recommended for use at 30 C were used at 37 C. Significant differences in measured levels of creatine kinase, lactic dehydrogenase, and aspartate aminotransferase due to different lots of expendable cuvettes were found for elevated levels of these enzymes. All kit reagents met manufacturers' claims for stability; however, different absolute levels of lactic dehydrogenase were observed with one kit reagent on successive days. Slight hemolysis affected creatine kinase levels measured with some reagent kits significantly more than others.