The Abnormal Reaction Data-detecting Function of the Automated Biochemical Analyzer Was Useful to Prevent Erroneous Total-bilirubin Measurement and to Identify Monoclonal Proteins

Background: Recently, to detect abnormal reactions and failures of the device in biological analysis, a reaction data monitoring system has been provided for automated biochemical analyzers. We investigated the usefulness of this function for total-bilirubin (T-Bil) measurement in routine testing.

Methods: Abnormal reactions of T-Bil were detected in the reaction data over time based on the following items: whether the absorbance variance after mixing of the first reagent and sample exceeds the cut-off value.

Results: In the cases in which the abnormal reaction was observed, the absorbance rapidly rose because of turbidity after mixing the sample with Reagent-1. The measured value was higher than the actual T-Bil level, for which the analyzer showed a warning mark with the output data. When this particular serum sample was subjected to immunofixation electrophoresis, the presence of a monoclonal protein was confirmed. We encountered seven similar cases out of 30,731 samples.

Conclusions: The reaction data monitoring system of the automated biochemical analyzers was useful to prevent false reports (misdiagnosis) due to unpredictable problems during T-Bil measurement. It was also suggested that detection of false reaction with a reagent may be a clue to find a new pathology, such as monoclonal gammopathy.