Diagnostic utility of postmortem blood cultures.

The autopsy is receiving renewed emphasis as a tool for quality assurance in clinical medicine. Postmortem blood cultures frequently are taken during the autopsy but are costly and of unclear diagnostic utility. To assess whether postmortem blood cultures contribute any useful information not already known from antemortem blood cultures, we compared positive postmortem blood cultures taken in 111 autopsies with the results of antemortem blood cultures. Of these, 60 (54%) of 111 had positive postmortem blood cultures despite a cause of death not related to an infectious cause. Of the 111 patients, 54 (49%) had antemortem blood cultures drawn in the 7 days before death, of which 34 (63%) of 54 were negative and 20 (37%) of 54 were positive. Of the 20 patients with true antemortem bacteremia/fungemia, seven (35%) had postmortem blood cultures that yielded the same organism, 10 (50%) yielded multiple organisms that were considered to be contaminants, and three (15%) yielded different organisms. These latter three cultures yielded microorganisms that were related to the patients' illness but did not provide additional information not already known from antemortem blood cultures or the patients' clinical or autopsy findings. Of the 91 patients who had no, negative, or contaminated antemortem blood cultures, 69 (76%) had postmortem blood cultures that yielded contaminants and 22 (24%) yielded microorganisms that were indeterminate as a cause of sepsis and, therefore, did not yield new or useful information. In summary, results of postmortem blood cultures rarely, if ever, provide information that is not already known, can be interpreted, provide new insights into pathophysiology, or detect errors in therapy.