Thanatochemistry: Study of synovial fluid potassium

Death interval estimation is one of the major attributes obtained from thanatochemistry. Body fluids like vitreous humour have been consistently used to estimate death interval from regression equations, but these may be useless when dealing with eye trauma, ocular disorders or in mutilated remains. Until recently, there was no consistent assessment of the reliability of measurements of the synovial fluid for death interval estimation. The purpose of this paper is to test previously developed regression formulae for estimating death interval based on synovial fluid potassium and to assess its reliability in estimating death interval. Synovial fluid potassium was measured on a sample of 308 individuals. Death interval was regressed on synovial fluid potassium and a regression formula was obtained. The regression model provided a 95% confidence interval of ±3.0 h and a correlation coefficient of 0.739. Compared to other studies, regression formulae based on the synovial fluid potassium in the present study provided considerably less standard errors.