Quality status of serum cholesterol analysis in Iceland

Eight laboratories participated in the first Icelandic quality assessment survey of serum cholesterol analysis in 1989. Quality control material, lyophilized animal serum and frozen human serum, was distributed three times over a period of one year and analyzed each time over 10 consecutive days. After two distributions of control material the laboratories were advised to start using a common calibrator from the U.S. National Bureau of Standards, and six months later the third lot of control material was analyzed. All laboratories use the same enzymatic methods for estimating serum cholesterol. Average total imprecision within and between laboratories improved throughout the survey, but did not reach the quality goal of the U.S. National Cholesterol Education Panel of +/- 3% for imprecision and +/- 3% for bias leaving scope for further improvement.