A suspected opioid overdose victim is brought dead. Which postmortem sample would be MOST suitable for toxicological confirmation of heroin (diacetylmorphine) use, given that heroin is rapidly hydrolysed to 6-monoacetylmorphine (6-MAM) and then to morphine?
- A Central blood — most representative of circulating drug levels
- B Gastric contents for unchanged diacetylmorphine if ingested
- C Urine or vitreous for 6-MAM, which persists longer than heroin in biological fluids ✓
- D Liver tissue for cytochrome P450 metabolite profiling
Explanation
6-Monoacetylmorphine (6-MAM) is the specific metabolite of heroin that is NOT formed from any other opiate; its presence in urine, vitreous, or blood specifically indicates heroin (not just morphine or codeine) use. Heroin itself has a plasma half-life of approximately 2–3 minutes; 6-MAM has a half-life of approximately 20–30 minutes. In postmortem specimens, urine has the highest 6-MAM yield due to renal concentration, but vitreous 6-MAM detection is valuable given the protected nature of vitreous from redistribution. Central blood may show only morphine, masking the heroin-specific evidence.
Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.