RELATIVE STABILITY AND PATTERNS OF CHANGE OF AMINO ACIDS IN POST-MORTEM BLOOD

Abstract

Prescription and illicit drug related deaths are common in medico-legal practice. In the investigation of these cases the interpretation of drug concentration in autopsy blood samples is of critical importance in establishing the cause of death and sheding light on the circumstances and manner of death. It is now accepted that drug concentrations in blood may be varied several folds between sampling sites and over times as a consequence of redistribution artefact, whereby drugs diffuse from reservoirs of high concentration, such as liver and lung, into the blood. Since this phenomenon profoundly affects the concentration of drugs in postmortem blood samples, it offers potential for serious misinterpretation of the significance of these drug levels. Based on current knowledge, the co'ncentration of drugs in blood from peripheral vessels, such as the femoral

vein, are interpreted as being most representative of the level at the time of death. Currently strategy is limited to minimise this problem by optimising sampling techniques. It would be helpful in the interpretation of postmortem drug levels in blood if there were a marker which indicated whether or not postmortem drug redistribution had occurred in an individual sample. Postmortem drug redistribution is hypothesised to be primarily a consequence of loss of cell membrane integrity, as a result of cellular death.