[Studies on the measurement of vitamin D derivatives in human plasma. I. A competitive protein binding assay for 25-hydroxyvitamin D in plasma (author's transl)].
A simple and precise method has been developed for the determination of 25-hydroxyvitamin D in 1 ml of human plasma. The method consists of methanol/chloroform extraction, purification by high pressure liquid chromatography and a competitive protein binding assay using vitamin D deficient rat serum. The ethanol extract from vitamin D deficient chick serum was added to the sample before CPBA to eliminate the non-specific interference in the CPBA system as a vitamin D free serum extract. The assay was sensitive to 0.72 ng/ml of plasma. Satisfactory results were obtained in the dilution and recovery tests. The coefficients of variation were 5.8 approximately 9.1% for the within-assay, and 7.4 approximately 10.3% for the between-assay. Plasma concentrations of 25-hydroxyvitamin D in 46 samples of normal human plasma were 21 +/- 10.5 ng/ml (mean +/- SD), and the seasonal variation was demonstrated. Plasma levels for 25-hydroxyvitamin D were high in patients receiving vitamin D2 and low in patients suffering from liver cirrhosis.
D015652:25-Hydroxyvitamin D 2; D000293:Adolescent; D000328:Adult; D000368:Aged; D001667:Binding, Competitive; D002112:Calcifediol; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004872:Ergocalciferols / Q000031:analogs & derivatives* / Q000097:blood; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D007223:Infant; D008103:Liver Cirrhosis / Q000097:blood; D008297:Male; D008875:Middle Aged; D011485:Protein Binding; D014808:Vitamin D Deficiency / Q000097:blood
D004872:Ergocalciferols; D006887:Hydroxycholecalciferols; D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol