Radiometric microbiologic assay

Radiometric Microbiologic Assays for the Measurement of Vitamin Folate, and Niacin in Human Blood and Food... 

Radiometric microbiological assays (RMA) for measuring the levels of vitamin B12, folate, and niacin in biological fluids and food were developed using Lactobacillus leichmannii, casei, and plantarum, respectively- In the presence of the appropriate Cdabeled substrate, these organisms readily produce directly proportional to the amount of the... 

Table IV. Radiometric Microbiological Assay Reproducibility of Serum Vitamin B12 Levels (pg/mL)...

Table V. Radiometric Microbiological Assay Reproducibility Study of Vitamin B12 Content in Food (30)...

Figure 4. Comparison of the vitamin B12 content of 22 varieties of food by the radiometric and turbidimetric microbiological assays correlation coefficient, r = 0.988. Foods include various mil baby food, fish, poultry, meat, and cereal. Each point represents the mean of five experiments.

When the red cell folate levels from 57 normal volunteers were determined by both the radiometric and the standard microbiological methods, the values obtained had a correlation coeflBcient of r = 0.98 (Figure 6). The mean red cell folate value obtained by the RMA was 270.0 ng/mL with a range of 149.4-769.2 ng/mL, using 5-methyl-H4Pte-Glu as the standard. By the turbidimetric assay, the mean red cell folate value was 281.7 ng/mL with a range of 142.7-707.1 ng/mL. 

Hausknecht EC. Wolf HJ. Radiometric assay for N-demechylltncomycin synthetase. American Society of Microbiology, Annual Meeting, 1986. 

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