Distribution of 6-monoacetylmorphine and morphine in head and pubic hair from heroin-related deaths

There is limited published data to aid interpretation of analytical findings from hair analysis. The aim of the study was to collate 6-monoacetylmorphine (6-AM) and morphine concentrations in head and pubic hair from heroin users and to propose reference ranges and relate these to the amount of heroin used. The ratio of morphine-to-6-AM was also investigated. A total of 82 head hair samples divided into 173 segments of various lengths and 15 pubic hair samples were collected at postmortem from heroin users. The hair was analysed using a previously published method. A statistical evaluation demonstrated that in head hair, the lower, middle and upper concentration ranges of 6-AM were 0.1–0.9, 0.9–12.5 and 12.5–154.1 ng/mg and those of morphine were 0.1–0.8, 0.8–6.0 and 6.0–36.3 ng/mg. In pubic hair, the lower, middle and upper concentration ranges of 6-AM were 0.2–0.5, 0.5–2.3 and 2.3–18.2 ng/mg and those of morphine were 0.2–0.4, 0.4–2.4 and 2.4–13.3 ng/mg. The morphine-to-6-AM ratio showed a large variation. The ratio tended to decrease from proximal to distal segments. The statistical results suggest low, middle and high concentration ranges which we propose can be used for estimating the amount of heroin consumed into corresponding low or occasional, regular or habitual and heavy or excessive drug use. The ratio of morphine-to-6-AM showed great variation and did not support the proposal that a ratio less than 0.77 is needed to prove ingestion of heroin.