BIOLOGICAL VARIABILITY OF CHOLESTEROL, TRIGLYCERIDE, LOW-DENSITY AND HIGH-DENSITY-LIPOPROTEIN CHOLESTEROL, LIPOPROTEIN(A), AND APOLIPOPROTEIN-A-I AND APOLIPOPROTEIN-B

Biological variability is a major contributor to the inaccuracy of car diovascular risk assessments based on measurement of lipids, lipoprote ins, or apolipoproteins. We obtained estimates of biological variation (CVb) for 20 healthy adults and calculated the percentiles of CVb as an expression of the variability of CVb among individuals for choleste rol, triglyceride, high-density lipoprotein (HDL) cholesterol, low-den sity lipoprotein (LDL) cholesterol, apolipoprotein (ape) A-l, apo B, a nd lipoprotein(a) Lp(a) by four biweekly measurements of these analy tes. The CVb for the group was similar to 6-7% for cholesterol, HDL ch olesterol, apo A-l, and apo B; similar to 9% for LDL cholesterol; and 28% for triglyceride. However, for each analyte, there was a considera ble variation of CVb among individuals. For all analytes except Lp(a), there was no relation between the individual's CVb and the analyte co ncentration. Lp(a) was inversely related to CVb, and there was a very wide variation in the CVb for Lp(a) among the participants, ranging fr om 1% to 51%. The number of independent analyses to perform to accurat ely assess an individual's risk for coronary artery disease should be determined on the basis of the individual CVb for a given analyte rath er than the average CVb.