Anti-Heroin is an active metabolite of heroin. 6-MAM is a unique metabolite to heroin and its presence in urine confirms that heroin was the opioid used. This is significant because on a urine immunoassay drug screen which typically tests for morphine, which is a metabolite of a number of a large number of opioids such as codeine, morphine sulfate, and heroin, 6-MAM is unique to heroin