Vitreous humour potassium rises predictably after death due to leakage from retinal cells. At an ambient temperature of 20°C, the approximate rate of rise of vitreous potassium used in forensic TSD (time since death) estimation is:

• A 1.5 mmol/L/hour
• B 0.17 mmol/L/hour ✓
• C 0.5 mmol/L/day
• D 2 mmol/L/hour

Explanation

The Sturner formula and subsequent studies estimate vitreous potassium rises at approximately 0.17 mmol/L/hour at room temperature (about 4 mmol/L per 24 hours from a baseline of ~5 mmol/L). This allows estimation of PMI (postmortem interval) using: PMI (hours) = (K+ − 7.14) / 0.17. Rates above 1.5 mmol/L/hour would lead to extremely rapid potassium accumulation inconsistent with observed postmortem chemistry. The method has a ±10-hour error margin.

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.