THE DEPENDENCE OF RADIOIMMUNOASSAY DETECTION LIMITS ON ANTIBODY-AFFINITY

Competitive radioimmunoassay standard curves for progesterone were est ablished with tritiated progesterone and six different anti-progestero ne monoclonal antibodies ranging in affinity from 1.23 X 10(8) to 2.82 X 10(10) 1/mol. The detection limits for these curves ranged from 133 to 6,670 pmol/l final assay concentration (16.7 to 839.1 pg/tube). Se parately, a mass-action mathematical model was used to predict lower d etection limits for assays run under equivalent conditions with the si x antibodies. When compared to the experimental data the predictions w ere reliable for the higher affinity antibodies but became less accura te as the affinity decreased. (C) 1997 Elsevier Science B.V.