Determination of eosinophil cationic protein in urine by an enzyme immunoassay.

An enzyme immunoassay has been developed which allows the determination in urine of eosinophil cationic protein (ECP). The antigen was prepared from urine from patients suffering from interstitial cystitis and found to be a 20,000 MW polypeptide. Eosinophil cationic protein has been determined in urine from normal people and in patients with interstitial cystitis and other bladder disorders. The results obtained using the enzyme immunoassay were compared with the results obtained with conventional radioimmunoassay. This new assay seems to be valuable in the diagnosis of interstitial cystitis.