A radioimmunoassay for bleomycin.

A radioimmunoassay for bleomycin, suitable for monitoring serum and urine drug levels, has been developed. Antisera were obtained from rabbits immunized with a conjugate of bleomycin and human serum albumin.Bleomycin labeled with 57Co was used as the tracer. Antibody-bound and free bleomycin were separated by precipitation with polyethylene glycol. The assay could determine bleomycin levels down to 0.025 mug/ml. The assay was precise, with a coefficient of variation of 2.8% Other drugs likely to be administered in combination with bleomycin did not interfere with the radioimmunoassay.