EVALUATION OF NONISOTOPIC BINDING ASSAYS FOR MEASURING VITAMIN-B-12 AND FOLATE IN SERUM

We report the evaluation of the microparticle enzyme immunoassay (MEIA ) for estimating vitamin B-12 and the ion capture (IC) assay for estim ating folate in serum. The assays were performed with the Abbott IMx a nalyzer. Intra-assay coefficients of variation were from 3.4% to 8.0% for vitamin B-12 and from 1.5% to 4.2% for folate, respectively. Inter assay coefficients of variation ranged from 6.3% to 8.8% for vitamin B -12 and from 3.9% to 11.3% for folate, respectively, Linearity was sat isfactory, with an analytical recovery of 119 +/- 4% for vitamin B-12 and 95 +/- 8% for folate. The detection limit was 56.2 pmol/l for vita min B-12 and 1.9 nmol/l for folate. Results of these assays correlated well with those from the cloned enzyme donor immunoassay (CEDIA), our current routine method: r = 0.97 for vitamin B-12 (n = 47) and r = 0. 97 for folate (n = 50). The MEIA and the IC assay were easy to perform with the IMx analyzer.