Radioassay for serum vitamin B12 with the use of saliva as the vitamin B12 binder

Ralph Carmel, Charles A. Coltman

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


A rapid, easy radioassay for serum vitamin B12 is described. Saliva, a readily available, rich source of vitamin B12-binding protein, is used. The assay is reproducible, correlates satisfactorily with microbiological assay results, and clearly differentiates between B12-deficient, normal, and high-B12 sera. Poor exclusion by some hemoglobin-coated charcoals of saliva-bound B12, in the absence of serum resulted in falsely low results. This problem can be corrected by acidification and redrying of the charcoal powder prior to coating or circumvented by additional coating of the hemoglobin-coated charcoal with vitamin B12-saturated serum.

Original languageEnglish (US)
Pages (from-to)967-975
Number of pages9
JournalThe Journal of Laboratory and Clinical Medicine
Issue number6
StatePublished - Dec 1969
Externally publishedYes

ASJC Scopus subject areas

  • Pathology and Forensic Medicine


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