Unreliability of radiodilution assays as screening tests for cobalamin (vitamin B12) deficiency

Publisher Website
Google Scholar
Abstract
Problems with the radiodilution assay method for measuring serum cobalamin (vitamin B12) levels were demonstrated. The standard commercial radiodilution kit assay is totally ineffective in screening for cobalamin deficiency. In a 4 mo. period, 352 patients were screened in a routine clinical laboratory using this kit. No serum sample yielded a result below the given normal range of 200-1100 pg/ml. When 42 patients with low-normal serum cobalamin levels (200-500 pg/ml) were retested by a modified radiodilution kit, a human intrinsic factor assay and a microbiological (Lactobacillus leichmannii) assay, 16 (36%) had abnormally low cobalamin levels. The diagnosis of cobalamin deficiency may have been incorrectly dismissed in many patients on the basis of test results obtained with these kits, which are in widespread use.

This publication has 2 references indexed in Scilit: