Repeatability of results from three in-house biochemistry analyzers and a commercial laboratory analyzer used in small animal practice

Abstract

The repeatability (precision) of clinical pathology results is vital for confidence in the measured values. Comparison to biological variation is an accepted standard for instrument/method performance in human clinical pathology. This study aims to assess precision of biochemistry results from three in-house analyzers and one commercial laboratory analyzer in relation to biological variation and to compare precision between the in-house analyzers and the commercial laboratory analyzer. Two commercially available quality control materials (QCMs) were repeatedly tested on the same and different days. Coefficients of variation were calculated and assessed in relation to published biological variation data for cats and dogs. In-house analyzer results were compared to results from the commercial laboratory. Seven of 13 analytes assessed met desirable quality precision standards for one QCM and minimum quality standards for the other QCM on all analyzers for both cats and dogs. For more than half of all determinations across all in-house analyzers, precision was as good as or better than the commercial laboratory analyzer. The precision of results from the analyzers assessed for most of the analytes tested is generally high, so large differences between repeated results from the same patient are probably due to biological changes rather than analyzer variation.