Specific 125I radioimmunoassay for morphine

In this specific radioimmunoassay procedure for morphine, samples are first subjected to an extraction procedure to remove the major metabolite of morphine (morphine-3-glucuronide), then quantified by use of a commercial radioimmunoassay kit with 125I-labeled morphine. Concentrations between 10 and and 100 micrograms/L are routinely measured with a within-run CV of less than 2.0% and a between-run CV of 3.5%. This rapid, specific, and sensitive method requires minimal technical skills and analytical equipment that is common to most laboratories.