Enzyme-linked immunosorbent assay and latex agglutination inhibition reaction test for cocaine and benzoylecgonine in urine

An enzyme-linked immunosorbent assay (ELISA) and a latex agglutination inhibition reaction test (LAIRT) for cocaine and benzoylecgonine have been established. In ELISA with polystyrene microtiter wells coated with anti-benzoylecgonine antibody and alkaline phosphatase (ALP)-labeled benzoylecgonine, the activity of antibody-bound ALP was measured with the enzyme cycling method. The range of benzoylecgonine measurable by ELISA was 12 pg-25 ng/well; the analysis time for 96 wells was 90 min. In LAIRT, the agglutination reaction with anti-benzoylecgonine antibody-coated latex and benzoylecgonine-rabbit serum albumin (RSA) conjugate-coated latex was inhibited by 0.1 mu g benzoylecgonine/ml urine; the analysis time for six samples on one glass slide was 20 min. The urine samples of 47 abusers were analyzed by ELISA and LAIRT. From the comparison with results of the enzyme-multiplied immunoassay technique (EMIT(R)) and gas chromatography-mass spectrometry (GC-MS), it was clarified that both ELISA and LAIRT were suitable for the screening method of urine samples.