Estimates suggest that more than 5.4 million U.S. citizens unknowingly have diabetes and are at increased risk of morbidity and mortality. We evaluated an immunoturbidimetric measurement of glycated hemoglobin (%HbA1c) as a postmortem tool to identify such individuals. Although postmortem samples undergo some degradation, the effects are not sufficient to invalidate the use of the test or method. Using two study populations whose medical history of diabetes was known, we found the mean %HbA1c of the non-diabetics (5.8 ± 0.3) to be statistically different from that of the diabetics (12.4 ± 2.8). For the population whose disease status was unknown, the %HbA1c ranged from 4.7 to 16.8. For six unknowns whose values exceeded 7.0%, the mean was 11.7%, which did not differ statistically from the diabetic mean (p = 0.6615). These studies suggest that postmortem blood samples can be used to characterize HbA1c values.