Cholesterol determinations from skin puncture and venous blood have similar imprecisions.

Comparison of cholesterol values from venous blood and skin puncture blood is difficult, because biological differences between both materials may be concealed or increased by the preanalytical imprecision of skin puncture. In 12 adults, we studied the variance of cholesterol and urea determination in 8 blood samples obtained by the puncture of 8 fingers and compared the results with the 8-fold determination of a venous sample drawn simultaneously. Our results show that the additional imprecision of skin puncture is low, and that the differences are not statistically significant. The mean values for cholesterol were 3.9% lower in skin puncture plasma than in venous plasma, whereas the mean values for urea were very similar.