Radioassay of serum folate.

Abstract

We describe a radioassay procedure for serum folate, in which commercially available crystalline β-lactoglobulin is used as the folate-binding agent. The folate binders present in serum are eliminated by heating serum in a boiling water bath for 15 min to denature the proteins. Radioassayable serum folate is shown to be stable under these conditions, and the results for folate compare well with those obtained by a microbiological assay.