Post-mortem vitreous humour is considered the best specimen for alcohol estimation because:
- A Vitreous is protected from putrefaction and post-mortem ethanol synthesis by microorganisms ✓
- B It has higher water content than blood, yielding higher levels that are easier to detect
- C Vitreous alcohol level directly equals blood alcohol level, simplifying interpretation
- D Alcohol equilibrates into vitreous faster than blood, reflecting earlier exposure
Correct answer: A. Vitreous is protected from putrefaction and post-mortem ethanol synthesis by microorganisms
Explanation
Vitreous humour is isolated from the systemic circulation by the blood-ocular barrier and its avascular composition resists microbial proliferation and endogenous production of ethanol by putrefaction organisms. The vitreous:blood alcohol ratio averages 1.2:1 (not 1:1); thus a measured vitreous level must be multiplied by 0.83 to approximate ante-mortem blood level. It is the gold-standard post-mortem specimen precisely because blood is susceptible to post-mortem synthesis of alcohol by bacteria.
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.