Quality-ControlScheme for Blood Glucose Measured Outsidethe Laboratory

We propose a quality-control (QC) scheme to evaluate the performance of blood glucose estimates made with a reflec-tometer in hospital wards or at home. We constructed a chart illustrating the comparison by regression analysis of the results of 254 reflectometer readings (y) and simultaneous capillary blood glucose analyses in the laboratory (.). Arbi-trary acceptance limits around the regression line (y = 0.5 + 0.87x; r = 0.97, S = 0.8 mmol/L) were established, based on the mean ±2 SD of the reflectometer readings of a series of classes of 1.1 mmol/L interval, made with the results from the laboratory analyzer. Each ward using a reflectometer is provided with the QC chart, and the first blood glucose estimation with the reflectometer on each working shift is controlled by re-assay in the laboratory. If the reflectometer reading is outside the limits, the next glucose estimation i