Brief communications Double logarithmic, linear relationship between plasma chloride concentration and time since death in humans in Chandigarh Zone of North-West India Dalbir Singh a, * , Rajinder Prashad b , Chandra Parkash a , Suresh Kumar Sharma c , Avadh Naresh Pandey a a Department of Forensic Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India b Department of Biochemistry, Postgraduate Institute of Medical Education, and Research, Chandigarh, India c Department of Statistics, Panjab University, Chandigarh, India Received 22 February 2002; received in revised form 30 May 2002; accepted 1 August 2002 Abstract Estimation of time since death with the change in chloride concentration in postmortem blood is the topic of discussion in the study. Querido (Forensic Sci Int 45 (1990) 117) had demonstrated a highly significant double logarithmic linear relationship between the plasma chloride concentration and postmortem interval in Wistar rats. Henceforth, the present study was carried out to substantiate this propensity in humans. Chloride concentration in postmortem blood of 474 subjects revealed a highly significant relationship between logarithm of plasma chloride concentration and logarithm of the time since death during 3 – 58 h of death. Notwithstanding, time since death can be predicted from plasma chloride concentration with standard error of estimate of 2.1 h but factors like environmental temperature, cause of death, age and gender influences it significantly. q 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Time since death; Postmortem interval; Plasma chloride concentration; Double logarithmic relationship 1. Introduction Many attempts have been made to estimate time since death which is an essential ingredient of every medicolegal postmortem examination but unfortu- nately there is no device by which it can be determined accurately. Madea and Henssage [1] were of the opinion that dissolution of the morphological, physical and chemical integrity of a dead body occurs due to autolytic process which commences soon after the stopage of energy metabolism in a cell. Cessation of active membrane transport and loss of selective membrane permeability occurs because of this energy breakdown resulting into diffusion of ions depending on their concentration gradient. As the extent of autolysis in a cadaver is dependent on time since death [1], number of researchers [2–11] have attempted to correlate time since death with the biochemical changes in various body fluids viz. blood, vitreous humor, cerebro-spinal fluid, etc. In blood, Jetter [2] was perhaps first to document that chloride concentration falls through intra-cellular shift at the rate of 80–90 mEq/l per day with the advancement of postmortem interval. Later Schliyer [3] observed that rate of fall was between 0.25 and 1 mEq/l per h, whereas Coe [4,12] was of the opinion 1344-6223/02/$ - see front matter q 2002 Elsevier Science Ireland Ltd. All rights reserved. doi:10.1016/S1344-6223(02)00056-1 Legal Medicine 5 (2003) 49–54 www.elsevier.com/locate/legalmed * Corresponding author. Tel.: þ 91-172-700-181/706-041; fax: þ 91-172-744-401/745-078.