A radioimmunoassay for the determination of 3 beta-hydroxy-5-cholenoic acid in human serum has been developed. using 3 beta-hydroxy-5-cholenoyl-thyroglobulin as immunogen and 3 beta-hydroxy-5-cholenoylglycyl-125I histamine as radioactive ligand. The association constant was 6. 3 X 10(8) l/mol. https://www.herbsdailyes.shop/product-category/serrapeptase/