To investigate the use of biochemical markers in combination for the postmortem diagnosis of hypothermia. To estimate physiological values for lactate in postmortem samples by an internal study.

Case #1: a 31-year-old female was found dead and naked. She had been undergoing treatment for thyroid disease. Case #2: a 55-year-old female was found dead in the wild. She had been undergoing psychiatric treatment for depression. Case #3: a 35-year-old male was found naked in a river. Alcoholic. Case #4: a 60-year-old female was found on her back in a field after an accident on the public highway. She had multiple sclerosis. Case #5: a 21-year-old male was found dead next to the highway in a sleeping bag. Case #6: a 77-year-old male was found dead hang on a mouldboard plough five days after his disappearance. Case #7: a 49-year-old female was found dead in the bush after hospitalization for depression.

Analysis of the biochemical markers (glucose, lactate, HbA1c and TSH) was conducted on vitreous humor, peripheral blood by electrochemiluminescence Roche Cobas^® 6000.

All values were<0.1mmol/L for glucose. Other values are presented in Table 1. An internal study was performed on 160 postmortem samples from different contexts of death (homicide, suicide, injuries) to propose physiological values for lactate in vitreous humor, which are unknown. Contrary to the other parameters whose physiological values were<0.1mmol/L for glucose (vitreous humor), from 0.27 to 4.20mUI/L for TSH (peripheral blood), and<5.6% for HbA1c (peripheral blood). The median physiological value for lactate was 26mmol/L. The determined physiological values for lactates were between 17 and 35mmol/L.

To identify the cause of death, different parameters must be considered. The combination of results for biochemical markers and other molecules such as acetone and isopropanol are the proof of ketoacidosis [1Palmiere C., et al. Usefulness of postmortem biochemistry in forensic pathology: illustrative case reports Legal Med 2012 ;  14 : 27-35 [cross-ref]

Cliquez ici pour aller à la section Références]. In addition, the effect of high levels of bromazepam was discussed in case #1. Furthermore, the differences between cases of diabetic ketoacidosis by hyperglycemia or insulin overdose were reported [2Hockenhull J., et al. Investigation of markers to indicate and distinguish death due to alcoholic ketoacidosis, diabetic ketoacidosis and hyperosmolar hyperglycemic state using postmortem samples Forensic Sci Int 2012 ;  214 : 142-147 [cross-ref]

Cliquez ici pour aller à la section Références]. The negative lactate values in these cases were one of the most important factors in identifying the cause of death. In fact, the collapse of lactate values in vitreous humor might be a pathognomonic sign of hypothermia and could establish a postmortem diagnosis.