Body temperature is elevated in the early postmortem period.

During the collection of specimens at autopsy for biochemical analysis, it was observed that body temperatures were higher than expected. To evaluate this observation further, rectal temperatures were determined at the earliest feasible time after death in 20 adult patients for whom recent premortem rectal temperatures were available for comparison. The average premortem temperature was 37.6 degrees C (range, 34.9 to 41.1 degrees C) and had been obtained 19 to 240 minutes (average, 107 minutes) before death. The average postmortem temperature, also 37.6 degrees C (range, 35.5 to 41.3 degrees C), was obtained 116 to 401 minutes (average, 202 minutes) after death. In the 11 patients in whom the postmortem interval was less than three hours (average, 155 minutes), there was an average postmortem temperature increase of 0.5 degree C (range, +1.3 to -0.7 degree C). The results suggest that there is usually an initial postmortem elevation in body temperature as measured rectally, probably as a result of continuing tissue and bacterial metabolism in the absence of the usual heat-dispersal mechanisms. This phenomenon should be considered when postmortem materials are used for analysis or when postmortem interval is determined by body temperature.