Fluorescence enzyme immunoassay of 17.ALPHA.-hydroxyprogesterone in dried blood samples on filter paper and its application to mass screening for congenital adrenal hyperplasia.

An enzyme immunoassay of 17α-hydroxyprogesterone (17-OHP) in dried blood spotted onto filter paper has been developed. 17-OHP was conjugated to horseradish peroxidase by the mixed anhydride method. Separation of free and bound 17-OHP-peroxidase conjugate was done by the use of insolubilized antibody, prepared by coating polyacetal beads with purified immunoglobulin G (IgG) of goat anti-rabbit IgG serum. The enzyme activity was measured by the fluorophoto-metric method using 3-(p-hydroxyphenyl)propionic acid and H2O2 as substrates. The sensitivity of the present method was 1.0 pg/tube for 17-OHP. The intra-and interassay coefficients of variation were 5.4-7.0% and 8.3-14.7%, respectively. The present enzyme immunoassay method could be applied to mass screening for congenital adrenal hyperplasia.