Improved sample and reagent pipetting with the MINILAB.

MINILAB is a small photometer designed for use in small labs and physicians' offices. The instrument is preprogrammed for the determination of several analytes either in whole blood, plasma or serum. Each method is provided as a kit containing disposable cuvettes and capillaries for sample or reagent addition. We examined the precision of the MINILAB using the cholesterol and bilirubin methods for serum, following the recommendations provided for each method, and found that the precisions were not acceptable (CV up to 16% for cholesterol and 43% for bilirubin). Suspecting that these variations were due to sample and reagent pipetting, we tried a simple modification using a Microcap for pipetting and were able to improve the precisions, resulting in CVs of 1.4% for cholesterol and 3.5% for bilirubin.