REFERENCE INTERVALS FOR PLASMA APOLIPOPROTEIN-A-I DETERMINED WITH A STANDARDIZED COMMERCIAL IMMUNOTURBIDIMETRIC ASSAY - RESULTS FROM THE FRAMINGHAM OFFSPRING STUDY

We have evaluated a commercially available, standardized immunoturbidi metric assay of apolipoprotein (ape) A-I, the major protein constituen t of high-density lipoproteins (HDL). We determined the reference rang es of plasma apo A-I concentration for white men and women and related these values to the risk of coronary heart disease (CHD). The mean be tween-run CV for this assay was 2.9%. As determined with individuals p articipating in cycle 4 of the Framingham Offspring Study, the mean (/- SD) apo A-I concentration was 13 % lower in 1879 men (1.34 +/- 0.23 g/L) than in 1939 women (1.54 +/- 0.28 g/L) (P <0.001). An apo A-I co ncentration of 1.20 g/L roughly corresponded to the 25th percentile va lue in men and the 5th percentile in women, and subjects with a concen tration below this value were significantly more likely to have CHD th an subjects with a higher concentration (P <0.001).