[A quantitative of serum biotin with microplate-assay using affinity streptavidin].

We modified Bayer's method of micro-plate assay for quantitation of biotin concentration. Biotin concentration in the solution and serum which cannot be quantitated directly by a microorganism assay (bio-assay), was easily determined by this method, which showed a high affinity of streptavidin for biotin this method and had a wide measurement range (0.9-60,000 pg/ml). We measured the concentration of biotin in 150 sera from 44 patients (21 males and 23 females) with active hepatitis (high level of both GOT and GPT, over 100 IU/l), 15 patients (7 males and 8 females) with inactive hepatitis (positive HCV-Ab but within normal limits of both GOT and GPT level), 17 patients (8 males and 9 females) with hepatoma and liver cirrhosis and 71 healthy persons (34 males and 37 females). The biotin concentration of sera in the healthy persons was 243.5 +/- 184.6 pg/ml, there being no sex difference. The biotin concentration in sera was higher in the patients than in healthy persons. It was high in the hepatoma and cirrhosis group (4,394.0 +/- 6,176.3), the active hepatitis group (2,397.4 +/- 2,785.5), and the inactive hepatitis group (1,873.2 +/- 1,523.7). These findings suggest that the biotin concentration is not significantly correlated with an escape enzyme such as GOT and GPT. These findings suggest that a high biotin concentration reflects other mechanisms such as escape from damaged liver cells.