Development of a single reagent polarisation fluoroimmunoassay for the detection of opiates in urine

The design, development, and optimisation of a simple polarisation fluoroimmunoassay to detect the opiate group of drugs, in urine, is described. Urine (10 microL) is added to 1.5 mL of a single reagent, prepared by mixing ovine anti-opiate serum with fluorescein-labelled morphine. After incubation for 30 min at 30 degrees C, or 60 min at room temperature, fluorescence polarisation is measured. The assay can be used as a "stat" test or automated for large batch screening and detects the commonly abused opiates, heroin (through its metabolite morphine), codeine, and dihydrocodeine.