INDIRECT ENZYME-LINKED METHOD FOR DETERMINING BIOTIN IN HUMAN SERUM

An indirect enzyme-linked assay was developed for quantifying biotin c oncentrations in human sera. Biotin standard solutions or unknown samp les are preincubated with streptavidin-conjugated horseradish peroxida se (streptavidin-HRP) and added to plates coated with biotinylated bov ine IgG (B-IgG(b)). The concentration of the streptavidin-HRP is such that the streptavidin binding sites are sufficient to bind apparently all the biotin present in samples, whereas, the remaining sites are in versely proportional to the amount of biotin in analysed sample. These sites could subsequently interact with the immobilized B-IgG(b) provi ding signal. The assay demonstrated dynamic range 5 to 640 ng/L, detec tion limit 2 ng/L, intra- and interassay C.V., 1.6-3.9% and 3.7-7.2% r espectively, recovery 100-114% and linear recovery 90-117%. Serum biot in determined: healthy individuals 66 to 600 ng/L, pregnant women (gre ater than or equal to 36weeks) 60 to 360 ng/L, and patients under chro nic haemodialysis 0.56 to 1.62 mu G/L. The method described is among t hose few which have been experimentally evaluated for their capabiliti ty of assessing biotin in human sera.