A sensitive ELISA for 6β-hydroxycortisol in urine using enzyme penicillinase (β-lactamase)

A sensitive and specific, enzyme labelled immunosorbent assay (ELISA) for 6 beta-hydroxycortisol in diluted urine using penicillinase was developed. 6 beta-Hydroxycortisol-21-hemisuccinate was conjugated with enzyme penicillinase. Antibody immobilized on a polyvinylchloride ELISA plate (Dynatech) was used for separation of bound from free ligand. The sensitivity of the assay was between 2.0-3.0 pg per well and recovery of 6 beta-hydroxycortisol from urine ranged between 85.0-108.0%. The assay is simple, rapid and precise.