[Clinical evaluation of a test strip for measuring creatinine in capillary blood of children].

Basing on an enzymatic method for determining creatinine, the new reagent strip "Reflotron Creatinin" of the Reflotron system recently was presented. In this study, it will be compared with another enzymatic test (Creatinin-PAP) and with a Jaffe-based assay (Creatinin-Jaffe for Hitachi 737). The quality control (within-days and within-series) yielded a sufficient accuracy and precision (CV = 4%) for the charge of used test strips. The recovery of double measured values was very good (r greater than 0.94). As regards the method comparison, differences in both charges were seen. The values of the former charge lay 7% on an average below the Jaffe-values, those of the latter 28% below. The slope of the latter regression line was considerably steeper. Comparing both enzymatic tests, the regression analysis gave poor results (y = -0.33 + 1.35 x). Bilirubin had not remarkable influences, whereas an evelated hematocrit slightly depressed the values. It seems necessary to start further studies to clear up the difference in test strip charges and to check more capillary blood samples of newborn and children with a pathologic creatinine level.