BackgroundApropos estimation of postmortem interval is an important and difficult task for forensic pathologists. In routine practice, postmortem interval is deduced by conventional or physical methods such as early and late postmortem changes, which are subjective methods and prone to errors. Estimating time since death by thanatochemistry is a more objective method as compared to routine conventional or physical methods. The present study is an attempt to analyze the changes in electrolytes level in serum after death and its correlation with postmortem interval.Materials and methodsBlood samples were taken from the deceased who were brought for a medicolegal autopsy. The concentration of electrolytes, mainly sodium, potassium, calcium, and phosphate, was evaluated in the serum. The deceased were grouped on the basis of time since death. Log-transferred regression analysis was done to establish the correlation of the concentration of electrolytes with time since death and regression formulas were derived for each parameter.ResultsSodium concentration in serum showed a negative correlation with time since death. Potassium, calcium, and phosphate showed a positive correlation with time since death. No statistically significant difference exists in the concentration of electrolytes between males and females. No significant difference was observed in the electrolytes concentration between the age groups.ConclusionConsidering the findings of this study, we infer that the concentration of electrolytes, primarily sodium, potassium, and phosphates, in the blood can be used to approximate the amount of time that has passed since death. Nonetheless, until 48 hours after death, electrolyte levels in the blood can be considered for the calculation of the postmortem interval.