A column radioassay for the quantification of vitamin B-12

A rapid and convenient column radioassay for the quantification of vitamin B-12 in clinical specimens has been developed. A mixture of the specimen and radiolabeled B-12 was applied to a column containing immobilized intrinsic factor and allowed to incubate for two hours. A buffer wash then separated bound and free B-12. The average intra- and inter-assay coefficients of variation over the range of interest was about 30 pg/ml in the sample and recovery and parallelism studies gave satisfactory results. The values obtained for clinical specimens by the column procedure correlated well with those obtained by reference method.