Is the formula of Traub still up to date in antemortem blood glucose level estimation?

Variance in intraindividual stability of vitreous humor for thanatochemistry

INTRODUCTION

This study investigates the intraindividual variability and ex-vivo stability of vitreous humor (VH) analytes for forensic thanatochemistry. VH, an anatomically isolated and robust postmortem fluid, provides valuable insights into the postmortem interval (PMI) and potential antemortem medical conditions.

MATERIALS AND METHODS

A total of 207 VH samples were collected from 36 cases and divided into three cohorts: serial sampling across three days postmortem, intraindividual variability assessment using triplicates, and ex-vivo stability evaluation through freeze-thaw cycles.

RESULTS

Linear relationships between PMI and potassium, calcium, creatinine, and lactate were identified, but their non-linear trends limited PMI estimation accuracy. Sodium, chloride, and glucose demonstrated variations linked to cardiovascular and infectious conditions, while elevated urea and creatinine correlated with renal or multi-organ failure. The study highlighted the importance of interpreting these biochemical markers in conjunction with clinical and environmental factors to improve reliability.

DISCUSSION

Ex-vivo stability testing revealed relevant variations in VH levels, emphasizing the need for standardized pre-analytical handling. Overall, while VH analytes offer promising forensic applications, their use for PMI estimation and medical diagnoses requires cautious interpretation within a multidisciplinary context.

Ethylene glycol poisoning may be associated with elevated post-mortem vitreous glucose level

Ethylene glycol (EG) is a toxic chemical that is sometimes used as ethanol substitute. Besides the desired intoxicating effects, the intake of EG may often lead to death unless timely treatment measures are provided by medical professionals. We examined 17 fatal EG poisonings between 2016 and March 2022 in Finland in terms of forensic toxicology and biochemistry results and demographic information. Most of the deceased were male and the median (range) age was 47 (20-77) years. Of the cases, 6 were suicides, 5 accidents and in 7 cases the intent remained undetermined. In all cases, vitreous humour (VH) glucose was above the limit of quantitation 0.35 mmol/L (mean: 5.2 mmol/L; range 0.52-19.5 mmol/L). Other markers of the glycaemic balance were within the normal range in all except one case. As EG is not routinely screened for in most laboratories but only analysed in cases where the intake of EG is suspected, some fatal EG poisonings may remain unrecognised in post-mortem (PM) investigations. Although various conditions may induce hyperglycaemia, it is worthwhile keeping in mind that elevated PM VH glucose levels that cannot be otherwise explained may suggest intake of ethanol substitutes.

Diabetes Related Deaths in a Tertiary Pediatric Referral Institution in England: The Value of Biochemical Analyses in Post-Mortem Samples

OBJECTIVES

To establish the incidence of "diabetes-related death" (DRD) in children with known and unknown Diabetes Mellitus (DM) dying unexpectedly, and describe post-mortem (PM) biochemistry findings.

PATIENTS AND METHODS

PM reports from the previous 16-year period were reviewed. Cases of DRD were extracted. All available demographic, clinical, and autopsy data including laboratory analyses was retrieved.

RESULTS

9/1376 (0.7%) DRD cases were identified. This was attributed to Diabetic Ketoacidosis in 7 and to Death in Bed Syndrome in 2. 4/9 cases were known diabetic and on insulin; whilst in 5/9 cases the diagnosis of DM was at PM. The mean age was 11.6 years (range 2.5-15). At PM, 4 cases were undernourished. The histology demonstrated pancreatic changes in keeping with DM in 3/9 and unremarkable pancreatic findings in 6/9. 3 cases also had autoimmune thyroiditis (1 also had myocarditis and Armanni-Ebstein nephropathy). Toxicological and biochemical analysis showed raised: β-hydroxybutyrate in 6, ketone bodies in 5 cases and raised HbA1c in 3c.

CONCLUSION

Type 1 DM is an infrequent but yet potentially preventable cause of death in children. Our findings highlight the value of routine biochemical and toxicological analysis in all PM examinations of infants and children dying suddenly and unexpectedly.

Markers of hyperglycemia in the vitreous humor. A systematic review and meta-analysis

BACKGROUND

Vitreous humor has been extensively used in forensic practice to assess hyperglycemia after death. The results from different articles, for various hyperglycemia markers are highly variable, and a systematic analysis of the results from studies currently used in forensic practice as landmarks has not yet been performed. Therefore, we aimed to evaluate to usefulness and limits of using the values of vitreous glucose, lactic acid, beta-hydroxybutyrate, and 1,5 Anhydro-d-glucitol to detect postmortem hyperglycemia.

MATERIALS AND METHODS

For this purpose, we performed a systematic review and a meta-analysis using the random-effects model to identify the threshold values and average differences for the markers mentioned above in the vitreous humor of diabetic versus nondiabetic subjects.

RESULTS

We included eleven studies in the meta-analysis and found the following mean differences between the diabetic and nondiabetic groups: for glucose - 91.4 mg/dl, for lactate - 34.17 mg/dl, for the Traub formula - 111 mg/dl, for fructosamine - 0.71 mmol/L, for beta-hydroxybutyrate - 36.55 mg/dl and 1,5 Anhydro-d-glucitol - -15.2 mg/dl. We also gave practical recommendations, based on the range of values and 95% confidence intervals in normal subjects and controls to identify antemortem hyperglycemia and evaluated, whenever possible, threshold values for fatal diabetes.

CONCLUSIONS

Glucose, Traub formula, fructosamine, and beta-hydroxy-butyrate can be used to detect postmortem hyperglycemia with some limitations; 1,5 Anhydro-d-glucitol can only be used to suggest the absence of a hyperglycemic status before death.

Usefulness of a blood glucose and ketone monitoring device as a screening tool for lethal diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is a frequent and life-threatening complication, whose diagnosis remains challenging in forensic practice. We aimed at assessing the performance of a commercially available blood glucose and ketone monitoring device (BGMD) in measuring glucose and ketone levels in post-mortem vitreous (VH) and blood samples, in order to determine if such a device can be used for screening lethal cases of DKA at autopsy. VH and blood samples were collected in cases of unexplained causes of death at autopsy. Glucose and β-hydroxybutyrate (BHB) were measured in VH and BHB in blood using the BGMD. The values were compared to those obtained with validated enzymatic methods. Values ≥ 10 mmol/L were considered to be elevated for glucose, and BHB values ≥ 2.5 mmol/L were considered to indicate ketoacidosis. There was a strong and significant correlation between VH glucose and blood BHB concentrations measured with the BGMD and the validated method (r = 0.78 and r = 0.80, p < 0.0001, respectively), whereas no correlation was found for VH BHB values (r = 0.19, p = 0.19). The sensitivity and specificity of the BGMD were both excellent (1.0) to detect elevated VH glucose levels with a threshold of 14.4 mmol/L, and to detect elevated blood BHB levels with a threshold of 2.85 mmol/L. In contrast, the specificity of the BGMD to detect high BHB levels in VH was poor (0.50) with an optimal threshold of 2.5 mmol/L. We showed that a commercially available BGMD is suitable for identifying cases of lethal DKA and other metabolic disorders at autopsy, through the investigation of vitreous glucose and blood BHB. We therefore recommend the systematic use of a BGMD for screening these conditions in cases of unexplained deaths.

Vitreous humor endogenous compounds analysis for post-mortem forensic investigation

The chemical and biochemical analysis of bodily fluids after death is an important thanatochemical approach to assess the cause and time since death. Vitreous humor (VH) has been used as a biofluid for forensic purposes since the 1960s. Due to its established relevance in toxicology, a literature review highlighting the use of VH with an emphasis on endogenous compounds has not yet been undertaken. VH is a chemically complex aqueous solution of carbohydrates, proteins, electrolytes and other small molecules present in living organisms; this biofluid is useful tool for its isolated environment, preserved from bacterial contamination, decomposition, autolysis, and metabolic reactions. The post-mortem analysis of VH provides an important tool for the estimation of the post-mortem interval (PMI), which can be helpful in determining the cause of death. Consequently, the present review evaluates the recent chemical and biochemical advances with particular importance on the endogenous compounds present at the time of death and their modification over time, which are valuable for the PMI prediction and to identify the cause of death.

Detection of RAGE expression and its application to diabetic wound age estimation

With the prevalence of diabetes, it is becoming important to analyze the diabetic wound age in forensic practice. The present study investigated the time-dependent expression of receptor for advanced glycation end products (RAGE) during diabetic wound healing in mice and its applicability to wound age determination by immunohistochemistry, double immunofluorescence, and Western blotting. After an incision was created in genetically diabetic db/db mice and control mice, mice were killed at posttraumatic intervals ranging from 6 h to 14 days, followed by the sampling of wound margin. Compared with control mice, diabetic mice showed the delayed wound healing. In control and diabetic wound specimens, RAGE immunoreactivity was observed in a small number of polymorphonuclear cells (PMNs), a number of macrophages, and fibroblasts. Morphometrically, the positive ratios of RAGE in macrophages or fibroblasts considerably increased in diabetic wounds during late repair, which exceeded 60% at 7 and 10 days post-injury. There were no control wound specimens to show a ratio of >60% in macrophages or fibroblasts. By Western blotting analysis, the ratios of RAGE to GAPDH were >1.4 in all diabetic wound samples from 7 to 10 days post-injury, which were >1.8 at 10 days after injury. By comparison, no control wound specimens indicated a ratio of >1.4. In conclusion, the expression of RAGE is upregulated and temporally distributed in macrophages and fibroblasts during diabetic wound healing, which might be closely involved in prolonged inflammation and deficient healing. Moreover, RAGE is promising as a useful marker for diabetic wound age determination.

The usefulness of point-of-care (POC) tests in screening elevated glucose and ketone body levels postmortem

The aim was to evaluate the performance of point-of-care (POC) tests in detecting glucose and ketone bodies in postmortem (PM) samples and to assess the usefulness of POC tests in sample screening for more precise analyses. Glucose and ketone body, β-hydroxybutyrate (BHB), were measured from vitreous humor (VH) in 52 autopsy cases with a POC blood glucose monitoring device (BGMD). In addition glucose and ketone bodies, acetone (Ac) and acetoacetate (AcAc), were measured from urine samples in another set of 59 cases with semi-quantitative stick tests. The results were compared to the concentration in VH measured with validated methods (values ≥ 7mmol/l indicate possible hyperglycemia and total ketone body levels ≥ 3mmol/l ketoacidosis). The sensitivity for glucose with the BGMD was 1.0 and specificity 0.94 when the threshold value for the meter to predict elevated glucose was set to ≥ 10mmol/l. The correlation between the BGMD and the validated method was strong (R(2)=0.89). For detecting ketoacidosis, the BGMD had a sensitivity of 1.0 and specificity of 0.73, when the threshold value was set to 2.5mmol/l. The urine stick test presented a sensitivity of 0.89 and specificity of 0.90 for detecting elevated VH glucose concentration. The sensitivity and specificity for the stick test to detect cases with possible ketoacidosis were 0.84 and 0.68, respectively. According to the results, BGMD can be reliably applied for sample screening, although more samples need to be analyzed for delineating the correct threshold values. In the case of glucose, the urine stick tests could be indicative in detecting cases with VH glucose ≥ 10mmol/l. For predicting possible ketoacidosis with elevated VH total ketone bodies, the stick test is not reliable as the test presented both false-positive and -negative results.

The Determination of Insulin Overdose in Postmortem Investigations

The analysis of biological specimens for the presence of exogenous insulin is of special interest in select postmortem investigations. Insulin analogues are primarily used to mediate the regulation of blood glucose concentrations; however, their use has also been implicated or suspected as a cause of death in suicides, accidents, and homicides. Toxicological analysis for these compounds is challenging due to the large molecular weight, the limited stability of insulin in whole blood, and complexities associated with sample preparation and instrumental testing. As a consequence, determination of insulin in postmortem specimens is not routinely offered by most forensic toxicology laboratories. Forensic death investigation is further complicated by interpretative difficulties such as the frequent absence of anatomical findings, concentration interpretation in known insulin users, and addressing the impact of chemical instability and postmortem redistribution. There are ongoing efforts, however, to develop and validate robust methods that may be used for this analysis on these challenging samples and that are capable of withstanding scientific and legal scrutiny for forensic use. In this regard, in recent years, methods for the detection of exogenous insulin in postmortem samples have been reported and results of this testing has been published in a handful of cases. The purpose of this article is to review the primary functions of insulin, the disease states associated with the therapeutic use of exogenous insulin, the current state of laboratory testing, and to provide case summaries that summarize the timeline of advancements and underscore the importance of this work.

Postmortem diagnosis of diabetes mellitus and its complications

Diabetes mellitus has become a major cause of death worldwide and diabetic ketoacidosis is the most common cause of death in children and adolescents with type 1 diabetes. Acute complications of diabetes mellitus as causes of death may be difficult to diagnose due to missing characteristic macroscopic and microscopic findings. Biochemical analyses, including vitreous glucose, blood (or alternative specimen) beta-hydroxybutyrate, and blood glycated hemoglobin determination, may complement postmortem investigations and provide useful information for determining the cause of death even in corpses with advanced decompositional changes. In this article, we performed a review of the literature pertaining to the diagnostic performance of classical and novel biochemical parameters that may be used in the forensic casework to identify disorders in glucose metabolism. We also present a review focusing on the usefulness of traditional and alternative specimens that can be sampled and subsequently analyzed to diagnose acute complications of diabetes mellitus as causes of death.

Xanthochromia of the skull bone associated with HbA1c

The color of the surface of 105 skull bones (part of the parietal bone) was determined using a portable spectral colorimeter (spectro color(®)). By this means it was possible to characterize the color objectively according to the L*a*b* color system defined by the "International Commission de l'Eclairage" (CIE). Biochemical markers of carbohydrate metabolism, HbA1c from venous blood, and glucose/lactate concentrations from vitreous humor, were also determined, for assessment of the ante-mortem plasma glucose concentration using Traub's sum formula. As biochemical markers for lipid metabolism disorder, cholesterol, triglycerides, high density lipoprotein (HDL), low density lipoprotein (LDL) and very low density lipoprotein (VLDL) were all determined from venous blood. There is a significant correlation of bone yellowing with HbA1c (p<0.001) and age (p<0.001). The literature asserts a significant correlation between diabetic condition and yellowing of the skull bone. Despite efforts to find the substance responsible for the yellowing of the bone in chronic metabolism disorder, no significant correlation was found between bone color and lipoproteins/bone extracted lipid acids.

Death due to diabetic ketoacidosis: Induction by the consumption of synthetic cannabinoids?

We present a case study on a man who suffered from diabetic ketoacidosis, probably following consumption of synthetic cannabinoids. In blood from a femoral vein AB-CHMINACA, AB-FUBINACA, AM-2201, 5F-AMB, 5F-APINACA, EAM-2201, JWH-018, JWH-122, MAM-2201, STS135 and THJ 2201 could be detected by LC-MS/MS. Diagnosis of ketoacidosis as cause of death was carried out using biochemical measurements of glucose and lactate concentrations in vitreous humour (sum formula: 463 mg/dl) and cerebrospinal fluid (sum formula: 506 mg/dl), of acetone (163 mg/l in femoral venous blood) and of HbA1c (98 mmol/mol). Death due to hyperglycaemia could have been induced by skipping of insulin doses due to his intoxicated state or by the cannabinoids which were described to be able to produce hyperglycaemia themselves.

Fatal metformin overdose: case report and postmortem biochemistry contribution

Metformin is an oral antihyperglycemic agent used in the management of type 2 diabetes mellitus. Lactic acidosis from metformin overdose is a rare complication of metformin therapy and occurs infrequently with therapeutic use. Fatal cases, both accidental and intentional, are extremely rare in clinical practice. Metformin is eliminated by the kidneys, and impaired renal function can result in an increased plasma concentration of the drug. In this report, we describe an autopsy case involving a 70-year-old woman suffering from diabetes mellitus and impaired renal function who received metformin treatment. Metformin concentrations in the peripheral blood collected during hospitalization and femoral blood collected during autopsy were 42 and 47.3 µg/ml, respectively. Lactic acidosis (29.10 mmol/l) was objectified during hospitalization. Furthermore, postmortem biochemistry allowed ketoacidosis to be diagnosed (blood β-hydroxybutyrate, 10,500 µmol/l). Death was attributed to lactic acidosis due to metformin intoxication. Increased plasma concentrations of the drug were attributed to severely impaired renal function. The case emphasizes the usefulness of performing exhaustive toxicology and postmortem biochemistry towards the more complete understanding of the pathophysiological mechanisms that may be involved in the death process.

Unconsciousness and sedation as precipitating factors of diabetic ketoacidosis

The aim of this study was to identify medico-legal situations characterized by increased vitreous glucose concentrations, potentially lethal blood 3-hydroxybutyrate levels and conditions that could either incapacitate or lead to death on their own. The above was investigated in order to verify whether prolonged states of unconsciousness may play a role in precipitating diabetic ketoacidosis. Six groups of medico-legal situations (corresponding to 206 autopsy cases) were identified. Among these, three cases were characterized by pathologically increased vitreous glucose and blood 3-hydroxybutyrate levels. In one case diabetic ketoacidosis coexisted with underlying features that might have potentially incapacitated or lead to death on their own, whereas in two cases it corresponded with potentially lethal or lethal drug concentrations. The results of this study highlight the usefulness of systematically performing biochemistry in order to identify diabetic ketoacidosis-related deaths, even when autopsy and toxicology results provide apparently conclusive findings.

Clinical and forensic examinations of glycaemic marker methylglyoxal by means of high performance liquid chromatography-tandem mass spectrometry

The postmortem determination of hyperglycaemic coma is quite difficult because of the lack of morphological findings and the difficult interpretation of biochemical parameters. Methylglyoxal (MG) is a reactive oxoaldehyde, which is mainly derived from glycolysis. An electrospray ionisation liquid chromatography-tandem mass spectrometric procedure for the determination of methylglyoxal in human serum and postmortem blood was developed. It involves protein precipitation with perchloric acid and a derivatisation step with 2,3-diaminonaphthalene. The assay was validated according to international guidelines. Serum samples from diabetics obtained at a diabetes clinic and from non-diabetics were used to assess data about reference concentrations in human serum. The assay showed linearity within the physiological concentrations in serum (5-500 ng/ml). Intraday imprecision at three concentrations was 10.3, 9.2 and 8.3 %, and interday imprecision was 15.3, 14.2 and 9.4 %; the limit of detection was 1.3 ng/ml, and limit of quantification, 3.2 ng/ml. One hundred and eighteen clinical (100 diabetics, 18 non-diabetics) and 98 forensic samples (84 non-diabetics, 14 in a status of hyperglycaemic coma) were measured. During life, diabetics showed significantly (p < 0.001) higher serum concentrations of MG than non-diabetics. After death, concentrations of MG increased significantly (p < 0.001). However, there was no correlation between the sum formula of Traub in vitreous humour and MG femoral blood concentrations (R = 0.237). This indicates that MG concentrations in the deceased cannot distinguish deaths due to a hyperglycaemic coma from other causes of death.