Measurement of apolipoproteins A-I and B during the National Health and Nutrition Examination Survey (NHANES) III

Abstract

We measured apolipoproteins (apo) A-I and B by rate immunonephelometry (rate INA) during Phase 1 of the National Health and Nutrition Examination Survey (NHANES) III. We also made the measurements by radial immunodiffusion (RID) in a 20% subset of the samples. Aliquots of this subset were also analyzed in the Northwest Lipid Research Laboratories by fixed-time INA calibrated to the World Health Organization (WHO)-International Federation of Clinical Chemistry (IFCC) First International Reference Materials for Apolipoproteins A-I and B. The CVs for the rate INA and RID measurements were: apoA-I, 4.5-7.7% and 2.5-7.6%, respectively; apoB, 2.3-5.3% and 2.3- 6.4%, respectively. In NHANES III, rate INA values (x) can be transformed to WHO-IFCC Reference Material-based values (y) as follows: for apoA-I, y = 0.87x + 251.8 mg/L (r = 0.93, SE(slope) = 0.13, SE(intercept) = 17, n = 708); for apoB (mg/L), y = 1.068x + 112.8 mg/L (r = 0.98, SE(slope) = 0.08, SE(intercept) = 7, n = 646).