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basis for pregnancy test
Several immunological reaction tests in common use are based upon the inhibition of hemagglutination (clotting of red cells). A positive test is obtained when human chorionic gonadotropin (HCG) in the woman’s urine or blood is added to human chorionic gonadotropin antiserum (rabbit blood serum containing antibodies to HCG) in the presence of particles (or red blood cells) coated with human...