Importance of Observing the Progress Curve During Enzyme Assay in an Automated Clinical Chemistry Analyzer: A Case Study

In the case presented here the reported result for total creatine phosphokinase led to the physician calling for report confirmation. The repeated test result was in keeping with the clinical picture and thus the previous erroneous result was amended. The incorrect result from auto analyzer was identified as failure to run the sample in dilution after instrumental flagging of possible substrate exhaustion evidenced by erroneous progress curve. A frequent reason for nonlinear progress curves is the presence of excess enzyme which can be easily misinterpreted as lower enzyme activity in a provided sample. Careful inspection of progress curve and predilution of sample in anticipated cases could avoid erroneous result.