HbA1c method evaluation for postmortem samples.

Glycated hemoglobin (HbA1c) is used for diagnosis of diabetes and evaluation of the glycemic control of diabetics in clinical medicine. It is also a useful biomarker for analyzing postmortem samples, since it is relatively stable and correlates well with clinical samples. We wanted to evaluate the information provided by HbA1c analysis of postmortem blood samples using a HPLC based, fully automated analyzer. Autopsy data from 55 cases, in which glucose, lactate, ketone bodies, and HbA1c were analyzed as a part of cause of death investigation, were selected for the study. Another set of 71 samples were analyzed in parallel with Mono S HPLC and automated BioRad D-10 HPLC. The results of 64 samples attained using both methods were compared using a Bland-Altman plot. We conclude that HbA1c can be analyzed reliably and cost-effectively from postmortem samples using a fully automated HPLC based analyzer. It is necessary, particularly in ketoacidotic cases, to determine the HbA1c level to help distinguish diabetic ketoacidosis from other causes.

Assessment of Traub formula and ketone bodies in cause of death investigations.

Diabetes and alcohol abuse may cause severe metabolic disturbances that can be fatal. These may be difficult to diagnose in autopsies based solely on macroscopical and histological findings. In such cases, metabolic markers, such as postmortem glucose and ketone levels, can provide supporting information. Glucose or combined glucose and lactate, the Traub value, is often used to indicate hyperglycemia. The use of the Traub value, however, has been questioned by some, because the lactate levels are known to elevate in postmortem samples also due to other reasons than glycolysis of glucose molecules. Ketoacidosis can be detected by analyzing ketone body levels, especially beta-hydroxybutyric acid (BHB). Acetone is also elevated in severe cases of ketoacidosis. Here, we have evaluated the value of these biomarkers for postmortem determination of the metabolic disturbances. Retrospective data of 980 medico-legal autopsies performed in Finland, where glucose, lactate and ketone bodies were analyzed, was collected. Our findings show that the Traub value indicates hyperglycemia, even when glucose levels are low. For diagnosis, evaluation of complementing markers, e.g. ketone bodies and glycated hemoglobin is needed. Our results show that BHB can be used for screening and diagnosis of ketoacidosis. Acetone alone is not sufficient, since it is elevated only in the most severe cases. We also found that alcohol abuse rarely causes severe ketoacidosis. However, sporadic cases do exist where ketone body levels are extremely high. Despite this, alcoholic ketoacidosis is very rarely diagnosed as the cause of death.

Measuring postmortem glycated hemoglobin - A comparison of three methods.

Glycated hemoglobin (HbA1c) is a glycoprotein formed as a result of the non-enzymatic addition of d-glucose to the hemoglobin ß-chain. The amount of HbA1c in the blood is dependent on mean glucose levels present during the 1-2 months preceding measurement, and it is an indicator of long-term glycemic levels. HbA1c is a useful marker in postmortem biochemistry in determining cause of death in acetonemic cases by allowing to distinguish diabetic ketoacidosis (DKA) from starvation or alcoholic ketoacidosis (AKA) and intoxication by acetone or isopropanol. We evaluated three methods for postmortem HbA1c measurement: Mono S cation exchange HPLC, affinity chromatography using point-of-care analyzer and a direct enzymatic method by. Additionally, optimization of sample storage and preservatives was performed and interpretation of the results in autopsy cases is discussed. Our results indicate that the HbA1c levels of postmortem samples can be reliably measured with Mono S HPLC. EDTA is the preferable preservative, as samples can be measured after as long as 4 weeks storage at +4°C. Our study shows that HbA1c analysis is a valuable tool alongside glucose and ketone body analysis in determining the metabolic state of deceased persons in medicolegal autopsies.

Postmortem measurement of C-reactive protein and interpretation of results in ketoacidosis.

C-reactive protein (CRP) is a widely used acute phase protein that reacts to various tissue-destroying stimuli. Its forensic applications have been established in prior studies. We show that CRP can be successfully measured even after a long postmortem period, up to 18 days, which has not previously been reported. Information on elevated CRP levels can be very valuable for the forensic pathologist in autopsy cases with scarce findings. The interpretation of results can be very challenging, as the elevation can originate from many different reasons, and due to the biochemical changes in cadavers. One less studied possible reason for elevated CRP is ketoacidosis. Here, we present a study on the effect of both alcoholic and diabetic ketoacidosis on blood CRP elevation in forensic autopsy material. Our results imply that ketoacidosis itself can cause a rise in CRP without other underlying causes, such as infection or trauma. However, more comprehensive studies are required to confirm the relationship between ketoacidosis and CRP level elevation.