New assay of apolipoproteins A-I and B by rate nephelometry evaluated.
We evaluated new, commercially available reagents for assaying apolipoproteins (apo) A-I and B by rate nephelometry (INA). Our initial linearity studies for apoA-I indicated that use of the commercial diluent resulted in incomplete immunoreactivity. Subsequent revision of the calibration line by the manufacturer compensated for this and improved the linearity for the apoA-I assay. We observed good linearity for the apoB assay. The within-run CVs were less than 4.0% and the between-run CVs were less than 5.5% for both assays. Results were 109% for apoA-I and 101% for apoB as compared with those measured for IUIS-WHO reference materials from the Centers for Disease Control. Recovery averaged 103% for apoA-I and 105% for apoB, for duplicate assays of three concentrations of purified apoA-I and low-density lipoprotein (LDL). Assaying sera from 45 patients, we demonstrated a good correlation between INA and radial immunodiffusion for both apoA-I (r = 0.92) and apoB (r = 0.95). Correlations between apoA-I and high-density lipoprotein cholesterol, and between apoB and LDL cholesterol compared favorably with previous reports. We conclude that these assays are accurate, precise, and easily automated for clinical application.
D016632:Apolipoprotein A-I; D001054:Apolipoproteins A / Q000097:blood*; D001055:Apolipoproteins B / Q000097:blood*; D001322:Autoanalysis; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D006801:Humans; D007118:Immunoassay; D005779:Immunodiffusion; D009391:Nephelometry and Turbidimetry; D011786:Quality Control; D011933:Reagent Kits, Diagnostic / Q000592:standards; D012044:Regression Analysis
D016632:Apolipoprotein A-I; D001054:Apolipoproteins A; D001055:Apolipoproteins B; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D011933:Reagent Kits, Diagnostic