Performance of dry-chemistry instruments in primary health care.

The results from an external quality control of dry-chemistry instruments are presented. The performance with regard to imprecision was good. With regard to accuracy, the performance was poor for aspartate aminotransferase, creatine kinase, lactate dehydrogenase, triglycerides and uric acid. The inaccuracy of alanine aminotransferase, bilirubin, cholesterol, creatinine, glucose and potassium was comparable to that obtained by hospital instruments using wet chemistry. There were no large differences with respect to quality between Seralyzer and Reflotron. However, Seralyzer users performed more analyses per week, analysed a higher number of constituents and had more experienced operators than the Reflotron users. Reflotron users more often analysed the sample in connection with the consultation. The importance of an established quality control programme for these instruments is underlined.