Detection of morphine in urine by hemagglutination inhibition, with use of lyophilized reagents.

We describe a modified test of hemagglutination inhibition for the detection of morphine in urine, similar to the well-known test for pregnancy. The reaction takes place in test tubes or ampoules containing carefully matched amounts of lyophilized morphine antiserum and tanned human erythrocytes coated with morphine conjugated to rat serum albumin. The reagents are reconstituted by adding 100 microL of urine and 400 microL of water, and the result is read after 60 min. The detection limit, tested with the method of Gorodetzky (Clin Chem 19:753, 1973), was about 200 ng of total morphine per milliliter of urine. For more than 2000 samples, results by our test agreed satisfactorily with those obtained by an accepted RIA method. The test is suitable for rapid screening in field work, monitoring subjects during detoxication, and use in nonspecialized laboratories. Confirmatory analysis is needed for quantitative measurements, forensic purposes, and discrimination between morphine and cross-reacting opiates.