2022 年 34 巻 2 号 p. 102-110
Although identifying antemortem pathological thrombi in autopsies is vital in assessing the cause of death, distinguishing them from simple blood clot masses only based on macroscopic appearance is sometimes challenging. This study examined the utility of increased methemoglobin concentrations in identifying antemortem pathological thrombi. From 49 autopsy cases, 98 blood clot samples were collected from the arterial （aorta） or venous （vena cava and proximal pulmonary artery） circulation. The samples were divided into a pathological thrombus group and a simple coagulation group based on macroscopic appearances. Methemoglobin concentrations （MetHb） were determined using a spectrophotometer, while the cutoff value was calculated by plotting the receiver operating characteristic curve. MetHb levels were significantly higher in the pathological thrombus group than in the simple coagulation group in arterial and venous samples （arterial: 15.1％ vs. 6.3％, venous: 15.2％ vs. 5.9％, respectively; p＜0.05）. The cutoff value was 11.1％ （area under the curve ［AUC］ 0.85） in arterial samples and 16.7％ （AUC 0.75） in venous samples. We also analyzed corrected values by subtracting MetHb values of the reference blood. This corrected value was also significantly higher in the thrombus group than the simple coagulation group in both arterial and venous samples （arterial: 10.1％ vs. 1.5％, venous: 10.1％ vs. 1.3％, respectively; p＜0.05）. The cutoff values were 4.6％ （AUC 0.87） in arterial samples and 3.7％ （AUC 0.73） in venous samples. The MetHb concentration in blood clot masses of autopsied bodies can help differentiate between antemortem pathological thrombi and simple postmortem coagulation masses.
