[Measurement of cholesterol in capillary blood using the Reflotron system. Results from approximately 1,000 comparisons with reference measurements of cholesterol in venous serum].

The results of 969 measurements of total cholesterol in capillary blood from fingerstick, performed with the Reflotron-system in the field, were compared with measurements of total cholesterol in venous serum. The comparison allows an evaluation of the combined effect of differences in sample material, working place, stability of methods and staff training. The mean values for all measurement were nearly identical with the two methods, and approximately 95% of the Reflotron-measurements were within an interval of +/- 0.7 mmol/l around the estimated true value. However, values below approximately 6 mmol/l were systematically underestimated, and values above approximately 7 mmol/l were overestimated with the Reflotron-system. The coefficient of variation of the system is below 5%, but both this precision and the accuracy appear to be unstable. Evaluated as a tool in screening for hypercholesterolemia, measurements with the system resulted in a modest extent of erroneous classification of subjects, but the positive diagnostic predictive value of the statement "cholesterol above 7 mmol/l" is only approximately 76%. Simulations of likely variations in the accuracy and precision of the method show a significant influence on the extent of errors. It is recommended that measurements with the system are routinely controlled by measuring an appropriate control material, at the start of each run and after every 30 samples.