Obtaining samples at post mortem examination for toxicological and biochemical analyses

Introduction The human body can be regarded as a complex assembly of dynamic chemical systems. Maintaining the integrity of these systems is an affront to the second law of thermodynamics and requires the constant expenditure of energy. Once death takes place, the supply of energy from metabolic processes is dramatically reduced, the integrity of the different compartments within the body breaks down at differing rates; complex molecules tend to break down to their simpler subunits and to move down concentration gradients that were maintained in life by the expenditure of metabolic energy. Obviously, these processes do not all occur at once. Thus, for a variable length of time after death the analysis of appropriate samples may yield useful information about the metabolic state of the person in the period immediately before death. Once death has taken place many drugs are released from their binding sites in tissue as pH decreases on death and as the processes of autolysis proceed. These phenomena can make the interpretation of drug concentrations after death less than straightforward.