A METHOD FOR PREPARING AN IMMUNOLO-GICO DIAGNOSTIC REAGENT FOR THE DETERMINATION OF PREGNANCY

摘要

1. An immunological diagnostic reagent for the determination of pregnancy by means of HCG determination and latex agglutination containing discrete particles of an immunologically inert latex polymer having a particle size of 0.01 to 0.9 mu m and a specific weight of 0.01 to 1.1, to which human choriongonadotropin (HCG) has been covalently bound via an amide bridge with a carbodiimide coupling agent at a pH of 5-8, characterized in that the HCG is used in the form of its beta-chain, whereby this beta-chain is substantially free from the alpha-chain and whereby this beta-chain has been separated from the alpha-chain by treating partially purified HCG containing 2000-5000 IU/mg of HCG for 1/2 to 2 hours at a pH of 4-5.5 and a temperature of 20-50 degrees C with a chaotropic agent, namely with a 7-10 molar aqueous solution of urea, a 7-10 molar aqueous solution of lithium bromide, a 4.5-6 molar aqueous solution of guanidine hydrochloride or a 2-3 molar aqueous solution of ammonium thiocyanate, subsequently adjusting the pH of the reaction mixture to 7.5 and separating the mixture of HCG/chaotropic agent by ion exchange and/or further conventional methods in accordance with which molecules can be separated on the basis of differences in the elektrostatic charge, and whereby neither the partially purified HCG nor the beta-chain thereof have been purified further.