Serum Folic Acid Activity by Improved L. casei Assay.

Abstract

1) An improved L. casei assay procedure for serum folic acid activity is described. Its range of usefulness over previous procedures is increased because of greater sensitivity, better accuracy in lower ranges, stability of test organism and micromethod applicability. 2) With this improved assay, the overlap of serum folic acid activity levels among normal subjects and folic acid deficient patients is so great that this determination has no value as an index of folic acid deficiency.