Radiometric microbiological estimation of vitamin B12

Estimation of vitamin B₁₂ in blood is very important to determine in decifiency and diagnosis of anemic patients. Vitamin B₁₂ in blood can be estimated by spectrochemical, enzymatic, radioisotopic and microbiological methods. In the present study vitamin B₁₂ was determined in 48 normal subjects of Rawalpindi/Islamabad by radiometric microbiological assay (RMA) technique using a very rapid, sensitive and automated instrument Bactec 460. In this procedure¹⁴C-glucose media and microorganismsLactobacillus leichmannii were used. The sensitivity of the method for vitamin B₁₂ is 1 pg/ml and the vitamin B₁₂ found in normal subjects was in the range of 105–535 pg/ml with a median value of 246±6 pg/ml.