A radioisotopic assay of vitamin B12 in serum is described. The assay is specifically designed to achieve maximum accuracy in the low serum B12 range in order to better delineate B12-deficient sera from sera with low, but normal, values of B12. The technique, utilizing the principle of saturation analysis, employs Cobalt-57 B12 added to the unknown sera as a tracer for the subsequent determination of per cent recovery of endogenous B12. Endogenous protein-bound B12 is liberated from the test sera, and a suitable quantity of B12-binding protein from pooled sera is added. The bound B12 is quickly separated from the free B12 by batchwise DEAE cellulose adsorption, and the per cent of protein-bound B12 concentration is determined. The procedure is reasonably rapid, is replicable, and is especially suitable for the clarification of borderline B12-deficient states.
|Original language||English (US)|
|Number of pages||13|
|Journal||The Journal of laboratory and clinical medicine|
|State||Published - Sep 1 1966|
ASJC Scopus subject areas
- Pathology and Forensic Medicine