Precision of estimating the time since death by vitreous potassium-Comparison of 5 different equations

- There is a huge literature on the postmortem rise of vitreous potassium.
- Clear data on the precision of death time estimation are missing.
- We compare 5 formulas for estimating the time since death by vitreous potassium.
- The best results were obtained using equations with “mean” slopes.
- In other climate zones equations with a steeper or flatter slope may be better.

The precision of death time estimation by vitreous potassium using 5 different formulas is compared on a random sample of 600 cases. Mean differences, standard deviations and 95% limits of confidence between real and extrapolated time since death were calculated. The best results were obtained using equations with “mean” slopes of about 0,17 or 0,19 mmol/l per hour. Equations with a steeper or flatter slope reveal already great mean deviations between real and extrapolated time since death and do not allow a reliable death time estimation.

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