Evaluation of a commercial radioisotopic kit for folate assays.

A commercial kit for the radioisotopic assay of folate in serum, the Bio-Rad 'Quanta Count' folate kit, produced lower results than the Lactobacillus casei microbiological assay method. Its normal range was 2-0-13-0 microng/l and the reproducibility was similar to that of the microbiological assay method. The kit was also satisfactory for whole bood folate assays. The cost requires careful consideration before the kit is used for routine purposes.