Immunoturbidimetric assays of apolipoproteins A, AI, AII, and B in serum.

In these immunoturbidimetric assays developed for apolipoproteins A, AI, AII, and B we used the Cobas-Bio centrifugal analyzer and commercially available antisera and calibrators. Within-day and within-run precision ranged from 1.0 to 5.8% for the four assays. The addition of bilirubin, up to 150 mg/L, or hemoglobin, 50 g/L, to sera did not interfere with the measurement of these apolipoproteins. Comparison of results of the immunoturbidimetric assays with those of radial immunodiffusion assays yielded slopes of 1.002, 0.822, and 0.957 and intercepts of -0.02, 0.47, and 0.03 g/L for apolipoproteins B, A, and AI, respectively. Reference intervals for the four apolipoproteins were determined by using sera from 193 apparently healthy individuals.