Analytical Toxicology

Longitudinal assessment of DNA recovery from post-mortem whole blood stored in EDTA, sodium fluoride/potassium oxalate and additive-free tubes

Adverse drug reactions and fatalities can result from therapeutic drug use due to genetic deficiencies in drug-metabolizing enzymes. In cases where ancillary testing may not reveal a clear cause of death, molecular autopsies can be valuable. However, forensic mortuaries do not retain DNA samples in all cases, which hinders subsequent genetic testing if it is later deemed necessary. This study aimed to evaluate whether post-mortem whole blood samples collected for toxicological analysis, could provide viable DNA for genetic testing after varying storage periods. Thirty deceased individuals were recruited with informed consent. Blood collected at autopsy from each individual was stored in two sodium fluoride/potassium oxalate (gray-top) tubes, two additive-free (red-top) tubes and one ethylenediaminetetraacetic acid (EDTA; purple-top) tube- the latter recommended for DNA analysis. Blood from one gray-top and one red-top tube were sampled for toxicological analysis prior to DNA analysis, while the remaining samples (acting as controls) underwent DNA analysis immediately. DNA analysis involved DNA extraction and DNA concentration and degradation assessment. Blood samples were stored at 4 °C and DNA extraction and analysis was repeated one year and then five years later. Toxicological sampling did not significantly influence DNA results. DNA concentration and quality significantly decreased over time for all sample types, with DNA from red-top tubes showing the greatest decline. The study showed that DNA testing for drug-metabolizing enzymes was feasible on whole blood that had been stored for five years. This finding supports the potential for retrospective genetic testing in cases of adverse drug reactions and fatalities.

The Role of Toxicology Investigations in Overdose Deaths

Overdose involves the administration of one or more narcotic substances in quantities exceeding the body's tolerance threshold, leading to toxic effects ranging from mild to fatal. The clinical manifestations of an overdose vary depending on the toxic substance's specific molecular action, such as stimulation or suppression of the nervous system. Common toxic agents include synthetic opioids like fentanyl, cocaine, barbiturates, benzodiazepines, and cannabinoids. This study emphasizes the critical role of forensic toxicology in identifying overdose deaths, focusing on the molecular mechanisms of toxicity, post-mortem redistribution, and the interpretation of toxicological findings. Advanced methodologies such as gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) are discussed as pivotal tools for identifying toxic substances and their metabolites. Biological matrices such as blood, urine, vitreous humor, and organ tissues are evaluated for their utility in toxicological investigations. Accurate interpretation of results informs not only the cause of death but also patterns of substance abuse, contributing to the development of preventive strategies. This study highlights the growing complexity of psychoactive substances, emphasizing the necessity for precise and innovative toxicological techniques in forensic practice.

Incidental detection of aluminum phosphide in abdominal subcutaneous fat- a rare reporting of chemical analysis findings in poisoning cases

Aluminum phosphide (AlP) poses a significant health challenge in developing countries, primarily because of its accessibility to the unregulated market and the absence of specific antidotes. Although chemical analysis of routine viscera can provide valuable information regarding the type of poison present in the body during poisoning incidents, numerous factors can alter the test results of chemical analysis, such as decomposition changes, postmortem redistribution, and the chemical nature of drugs. Analytical methods are frequently impeded by the interference caused by coextracted putrefactive compounds, which can mask or alter the detection of drugs. This series of three cases is particularly noteworthy because it involves the postmortem detection of AlP in the abdominal subcutaneous fat of the deceased, a previously unreported occurrence. In the first case, the body showed findings of late postmortem changes, with stomach mucosa being congested and hemorrhagic, along with routine viscera, and abdominal subcutaneous fat was sent for toxicological analysis. To confirm these findings, in two further cases of suspected AlP poisoning, subcutaneous fat was sent along with routine viscera. Stomach mucosa in the other two cases showed findings similar to those in the first. In the third case, black paste-like material was noted as stomach content. All the cases revealed the presence of AlP in routine viscera samples and abdominal subcutaneous fat on gas chromatography-mass spectrometry (GC‒MS) analysis. Therefore, abdominal fat can serve as a suitable sample for toxicological analysis to identify the presence of AlP, even in cases with advanced putrefactive changes.

Difficulties associated with the interpretation of postmortem toxicology

While postmortem (PM) toxicology results provide valuable information towards ascertaining both the cause and manner of death in coronial cases, there are also significant difficulties associated with the interpretation of PM drug levels. Such difficulties are influenced by several pharmacokinetic and pharmacodynamic factors including PM redistribution, diffusion, site-to-site variability in drug levels, different drug properties and metabolism, bacterial activity, genetic polymorphisms, tolerance, resuscitation efforts, underlying conditions, and the toxicity profile of cases (i.e. single- or mixed-drug toxicity). A large body of research has been dedicated for better understanding and even quantifying the influence of these factors on PM drug levels. For example, several investigative matrices have been developed as potential indicators of PM redistribution, but they have limited practical value. Reference tables of clinically relevant therapeutic, toxic, and potentially fatal drug concentrations have also been compiled, but these unfortunately do not provide reliable reference values for PM toxicology. More recent research has focused on developing databases of peripheral PM drug levels for a variety of case-types to increase transferability to real-life cases and improve interpretations. Changes to drug levels after death are inevitable and unavoidable. As such, guidelines and practices will continue to evolve as we further our understanding of such phenomena.

From Deutsche Zeitschrift to International journal of legal medicine-100 years of legal medicine through the lens of journal articles, Part 4: International journal of legal medicine from 1990 to 2022

This is the fourth and final paper in a series related to the analysis of articles published in this journal during its first 100 years of activity. This article covers the time span from 1990 to 2022. It is important to note that, given the period covered by this analysis, it does not aim to provide a historical overview but rather an examination of the most recent trends in our discipline compared to the past. Between 1990 (Volume 104) and 2022 (Volume 136), 4004 articles were published in the International Journal of Legal Medicine (IJLM) across 33 volumes. This corresponds to 53% of all the articles published since the launch of the journal. When compared to the period from 1970 to 1990, some categories no longer appear to be as relevant (e.g., sexual medicine, 1 article; social medicine, 0 articles; biography, 3 articles; history, 4 articles). Conversely, the most recent period has shown an increasing importance in forensic genetics (1388 articles) and the emergence of new significant topics that merit their own classification, such as age estimation (286 articles), forensic anthropology (189 articles), forensic imaging (150 articles), and forensic entomology (90 articles).

Stability of synthetic cathinones in clinical and forensic toxicological analysis-Where are we now?

Understanding the stability of analyzed drugs in biological samples is a crucial part for an appropriate interpretation of the analytical findings. Synthetic cathinones, as psychoactive stimulants, belong to a major class of new psychoactive substances. As they are subject to several degradation pathways, they are known to clinical and forensic toxicologists as unstable analytes in biological samples. When interpreting analytical data of synthetic cathinones in biological samples, analysts must be aware that the concentration of analytes may not accurately reflect the levels at the time they were acquired owing to many factors. This review provides (i) an overview of the current scientific knowledge on the stability of synthetic cathinones and/or metabolites in various human biological samples with a focus on factors that may deteriorate their stability-such as storage temperature, length of storage, matrix, pH, type of preservatives, concentration of analytes, and the chemistry of the analytes-and (ii) possible solutions on how to avoid such degradation. The PubMed database as well as Google Scholar was thoroughly searched to find published studies on the stability of synthetic cathinones since 2007 by searching specific keywords. A total of 23 articles met the inclusion criteria and were included in this review. Synthetic cathinones that carry methylenedioxy or N-pyrrolidine ring showed higher degradation resistance over other substituted groups. Acidification of samples pH plays a crucial role at increasing the stability of cathinones even with analytes that were frequently considered as poorly stable. This review also provides several recommendations for best practice in planning the experimental design, preservation, and storage conditions in order to minimize synthetic cathinones' degradation in human biological samples.

Intentional Carbofuran poisoning in 7 dogs

Background

Carbofuran is a widely used broad-spectrum pesticide that, despite strict regulation and being banned for more than a decade, is still encountered in cases of intentional poisoning in dogs and wildlife. The objective of the study was to provide a complete and detailed description of the pathological, histological and toxicological findings of 7 cases of intentional carbofuran poisoning in dogs.

Results

In this retrospective study, 7 cases of carbofuran intoxication recorded from July 2015 to June 2017 were analyzed. Following complete history recording, all cases were examined by complete necropsy and histopathology. Carbofuran intoxication was confirmed in all cases by gas chromatography. The postmortem examination revealed extensive hemorrhaging and congestion located mainly within the respiratory, nervous and cardiovascular systems, accompanied by degeneration and necrosis within the lungs, heart, and kidneys.

Conclusions

Although carbamates have been banned in the European Union, carbamate poisoning is still frequently encountered, especially in wild animals. This paper will contribute to a better understanding of the occurrence and pathogenesis of acute carbofuran exposure in dogs and contribute some peculiar pathological features of this type of poisoning to the current literature.

New strategy for carbon monoxide poisoning diagnosis: Carboxyhemoglobin (COHb) vs Total Blood Carbon Monoxide (TBCO)

Diagnosis of carbon monoxide (CO) poisonings has always been a challenging task due to the susceptibility to alterations of the optical state and degradation of blood samples during sampling, transport and storage, which highly affects the analysis with spectrophotometric methods. Methodological improvements are then required urgently because of increased reports of cases with discrepancies between results of the measured biomarker carboxyhemoglobin (COHb) and reported symptoms. Total blood CO (TBCO) measured chromatographically was thus proposed in a previous study as alternative biomarker to COHb. This approach was investigated in this study by comparing the two biomarkers and assessing the effects of various storage parameters (temperature, preservative, time, tube headspace (HS) volume, initial saturation level, freeze- and thaw- and reopening-cycles) over a period of one month. Results show that while for TBCO, concentrations are relatively stable over the observation period regardless of parameters such as temperature, time and HS volume, for COHb, concentrations are altered significantly during storage. Therefore, the use of TBCO as alternative biomarker for CO poisonings has been proposed, since it provides more valid results and is more stable even under non-optimal storage conditions. Additionally, it can be used to predict COHb in cases where sample degradation hinders optical measurement. Furthermore, a correction formula for COHb and TBCO is provided to be used in laboratories or circumstances where optimal storage or analysis is not possible, to obtain more accurate results.

Interpreting γ-hydroxybutyrate concentrations for clinical and forensic purposes

INTRODUCTION

γ-Hydroxybutyric acid is an endogenous substance, a therapeutic agent, and a recreational drug of abuse. This psychoactive substance acts as a depressant of the central nervous system and is commonly encountered in clinical and forensic practice, including impaired drivers, poisoned patients, and drug-related intoxication deaths.

OBJECTIVE

The aim of this review is to assist clinical and forensic practitioners with the interpretation of γ-hydroxybutyric acid concentrations in blood, urine, and alternative biological specimens from living and deceased persons.

METHODS

The information sources used to prepare this review were PubMed, Scopus, and Web-of-Science. These databases were searched using keywords γ-hydroxybutyrate (GHB), blood, urine, alternative specimens, non-conventional biological matrices, saliva, oral fluid, sweat, hair, vitreous humor (VH), brain, cerebrospinal fluid (CSF), dried blood spots (DBS), breast milk, and various combinations thereof. The resulting 4228 references were screened to exclude duplicates, which left 1980 articles for further consideration. These publications were carefully evaluated by taking into account the main aims of the review and 143 scientific papers were considered relevant. Analytical methods: The analytical methods used to determine γ-hydroxybutyric acid in blood and other biological specimens make use of gas- or liquid-chromatography coupled to mass spectrometry. These hyphenated techniques are accurate, precise, and specific for their intended purposes and the lower limit of quantitation in blood and other specimens is 0.5 mg/L or less. Human pharmacokinetics: GHB is rapidly absorbed from the gut and distributes into the total body water compartment. Only a small fraction of the dose (1-2%) is excreted unchanged in the urine. The plasma elimination half-life of γ-hydroxybutyric acid is short, being only about 0.5-0.9 h, which requires timely sampling of blood and other biological specimens for clinical and forensic analysis. Endogenous concentrations of GHB in blood: GHB is both an endogenous metabolite and a drug of abuse, which complicates interpretation of the laboratory results of analysis. Moreover, the concentrations of GHB in blood and other specimens tend to increase after sampling, especially in autopsy cases. This requires the use of practical "cut-off" concentrations to avoid reporting false positive results. These cut-offs are different for different biological specimen types. Concentrations of GHB in clinical and forensic practice: As a recreational drug GHB is predominantly used by young males (94%) with a mean age of 27.1 years. The mean (median) and range of concentrations in blood from apprehended drivers was 90 mg/L (82 mg/L) and 8-600 mg/L, respectively. The concentration distributions in blood taken from living and deceased persons overlapped, although the mean (median) and range of concentrations were higher in intoxication deaths; 640 mg/L (280 mg/L) and 30-9200 mg/L, respectively. Analysis of GHB in alternative specimens: All biological fluids and tissue containing water are suitable for the analysis of GHB. Examples of alternative specimens discussed in this review are CSF, saliva, hair strands, breast milk, DBS, VH, and brain tissue.

CONCLUSIONS

Body fluids for the analysis of GHB must be obtained as quickly as possible after a poisoned patient is admitted to hospital or after a person is arrested for a drug-related crime to enhance chances of detecting the drug. The sampling of urine lengthens the window of detection by 3-4 h compared with blood samples, but with longer delays between last intake of GHB and obtaining specimens, hair strands, and/or nails might be the only option. In postmortem toxicology, the concentrations of drugs tend to be more stable in bladder urine, VH, and CSF compared with blood, because these sampling sites are protected from the spread of bacteria from the gut. Accordingly, the relationship between blood and urine concentrations of GHB furnishes useful information when drug intoxication deaths are investigated.

A scream from the past: a multidisciplinary approach in a concealment of a corpse found mummified

When a mummified body is found, it requires the forensic pathologist to determine the manner and cause of death. The mummified body of an older man was found walled in an alcove in a silicon-sealed bedroom, in a semi-supine position with the back on the floor and the legs on the wall. Two plastic bags covered the body. Having removed the plastic bags, the body was fully wrapped in a brown adhesive tape. At the scene, there was no evidence of microfauna. The subject's son stated that after his father's death, he concealed the corpse in order to obtain his annual pension. A postmortem CT scan was performed before the autopsy, which excluded traumatic injuries. The autopsy together with the toxicological and microscopic findings helped us to understand the manner of death. In this case, the mummification process developed under specific environmental conditions and a multidisciplinary approach was required in order to solve it.

Genetic and toxicologic investigation of Sudden Cardiac Death in a patient with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) under cocaine and alcohol effects

Cocaine and alcohol toxicity is well known, especially when simultaneously abused. These drugs perform both acute and chronic harmfulness, with significant cardiac events such as ventricular arrhythmias, tachycardia, systemic hypertension, acute myocardial infarction, ventricular hypertrophy, and acute coronary syndrome. The present report refers about a patient who died after a documented episode of psychomotor agitation followed by cardiac arrest. At the autopsy investigation, arrhythmogenic right ventricular cardiomyopathy (ARVC) was diagnosed and confirmed by postmortem molecular analysis revealing a mutation in the DSG2 gene. Postmortem toxicological analysis demonstrated a recent intake of cocaine, and the death was attributed to cardiac arrhythmias. The detection of cocaine and cocaethylene in hair samples proved chronic simultaneous intake of cocaine and alcohol at least in the last month. The authors discuss the role of these drugs and genetic predisposition of the ARVC in causing the death of the patient.

Acute Alcohol Toxicity

Acute alcohol (ethanol) toxicity is a definition that encompasses both the metabolic toxicity of alcohol and the association of alcohol with traumatic deaths, suicide, and criminal activities. As with any postmortem measurement, there must be control of postmortem sampling, storage of specimens, and appropriate analysis to ensure that there is not artifactual alcohol production or incorrect measurement of other postmortem alcohols. It is almost unheard of for acute alcohol toxicity to cause death secondary to metabolic effects in a naïve individual, although there has been a recent trend in social media dares that have led to deaths due to isolated episodes of extreme alcohol consumption. However, in most cases, there will be evidence for chronic alcohol misuse at the postmortem examination.

Direct quantitation of methyl phosphonate adducts to human serum butyrylcholinesterase by immunomagnetic-UHPLC-MS/MS

Hydrolysis of G- and V-series organophosphorus nerve agents (OPNAs) containing a phosphorus-methyl bond yields a methylphosphonic acid (MeP) product when adducted to human butyrylcholinesterase (BChE). The MeP adduct is considered a sign of "aging" and results in loss of the o-alkyl identifier specific to each nerve agent. After aging has occurred, common therapeutics such as oximes cannot reactivate the cholinesterase enzyme and relieve cholinergic inhibition. Until now, a direct, quantitative method for determination of the MeP adduct to BChE was unavailable. Aged adducts in serum samples were processed by immunomagnetic separation of BChE by antibody conjugated bead, isotope-dilution, pepsin digestion, followed by UHPLC separation and detection by conventional electrospray ionization-tandem mass spectrometry (ESI-MS/MS). Ions were detected in selected reaction monitoring (SRM) mode, and transition m/z 874.3 → 778.3 was used for quantitation. The analytical response ratio was linearly proportional to the serum concentration of MeP-adducted peptide (MeP-P) over the nominal concentration range of 2.0-250 ng/mL, with a coefficient of determination of R(2) ≥ 0.997. Intrarun accuracy, expressed as %Relative Error (%RE), was ≤13.5%, 16.3%, and 3.20% at 2.0, 16, and 250 ng/mL, respectively; the corresponding precision expressed as %RSD was ≤11.9%, 6.15%, and 3.39%. Interday %RSD was ≤7.13%, 5.69%, and 1.91%. Recovery of MeP-P from serum was ≥68% across the validated concentration range, and contributions from matrix effects were minimal. The method provides a direct, quantitative measurement of MeP-P found in clinical samples suspected of nerve agent exposure and subjected to such post-sampling stresses as elevated temperature and extended shipping.

How can analytical diagnostics in clinical toxicology be successfully performed today?

This article discusses current strategies for efficient analytical diagnostics in clinical toxicology. The tasks for such diagnostics, different analytical strategies and various methods were reviewed. They cover mainly gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry procedures for target or comprehensive screening for drugs (of abuse) and poisons, and for quantification in blood. Quality control aspects and strategies for competent interpretation of the analytical result in correlation with the clinical signs presented by the patient are discussed.

Classical Mistakes in Forensic Toxicology Made by Forensic Pathologists

The forensic pathologist interprets the toxicology results in the setting of the entire death investigation. This review focuses on potential errors by the forensic pathologist with regard to toxicology analysis encountered with death investigation. These include mistakes of determining the cause of death based solely on the drug concentration and failure to consider the postmortem nature of the specimen when interpreting results. The forensic toxicologist does analytical toxicology; i.e., determining what drug(s) is/are present and in what concentration. The forensic pathologist does interpretive toxicology, which requires consideration of the decedent's medical history, the circumstances surrounding death, the environment of the death, the autopsy findings, and the results of the analytical toxicology. Forensic pathologists must communicate with the forensic toxicologists, understand their limitations, and collect proper specimens. Providing appropriate clinical information to the toxicologists will result in more timely and thorough toxicological analysis. Toxicologic results should be included on the death certificate only when they make a pathologic contribution to death.

Postmortem redistribution of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH)

INTRODUCTION

Postmortem redistribution (PMR), a well-described phenomenon in forensic toxicology for certain drugs, can result in increased central blood concentrations relative to peripheral blood concentrations. Δ(9)-tetrahydrocannabinol (THC), the primary psychoactive component in cannabis or marijuana, is the illicit substance most commonly implicated in driving under the influence of drugs (DUID) cases and fatally-injured drivers. No investigation of PMR of THC in human blood has been reported to date.

METHODS

Matched heart and iliac postmortem blood specimens were collected from 19 medical examiner cases (16 Males, 3 Females) with positive cannabinoid urine immunoassay screens. THC, its equipotent metabolite 11-hydroxy-THC (11-OH-THC) and non-psychoactive metabolite 11-nor-9-carboxy-THC (THCCOOH) were quantified by two-dimensional gas chromatography-mass spectrometry with cryofocusing, with 0.5 ng/mL limits of quantification (LOQ) for all analytes.

RESULTS

10 cases had quantifiable THC and 11-OH-THC; THCCOOH was present in all 19. Median (range) heart:iliac blood ratios were 1.5 for THC (range: 0.3-3.1); 1.6 for 11-OH-THC (range: 0.3-2.7); and 1.8 for THCCOOH (range: 0.5-3.0).

DISCUSSION

Cannabinoids, in general, exhibited a mean and median central:peripheral (C:P) concentration ratio of less than 2 following death. A trend was observed for greater PMR with increasing postmortem interval between death and sampling. To our knowledge, these are the first data on THC PMR in humans, providing important scientific data to aid in the interpretation of postmortem cannabinoid concentrations in medico-legal investigations.

Collection of biological samples in forensic toxicology

Forensic toxicology is the study and practice of the application of toxicology to the purposes of the law. The relevance of any finding is determined, in the first instance, by the nature and integrity of the specimen(s) submitted for analysis. This means that there are several specific challenges to select and collect specimens for ante-mortem and post-mortem toxicology investigation. Post-mortem specimens may be numerous and can endow some special difficulties compared to clinical specimens, namely those resulting from autolytic and putrefactive changes. Storage stability is also an important issue to be considered during the pre-analytic phase, since its consideration should facilitate the assessment of sample quality and the analytical result obtained from that sample. The knowledge on degradation mechanisms and methods to increase storage stability may enable the forensic toxicologist to circumvent possible difficulties. Therefore, advantages and limitations of specimen preservation procedures are thoroughfully discussed in this review. Presently, harmonized protocols for sampling in suspected intoxications would have obvious utility. In the present article an overview is given on sampling procedures for routinely collected specimens as well as on alternative specimens that may provide additional information on the route and timing of exposure to a specific xenobiotic. Last, but not least, a discussion on possible bias that can influence the interpretation of toxicological results is provided. This comprehensive review article is intented as a significant help for forensic toxicologists to accomplish their frequently overwhelming mission.

Drug poisoning deaths in Sweden show a predominance of ethanol in mono-intoxications, adverse drug-alcohol interactions and poly-drug use

Over a 10-year period (1998-2007) all deaths in Sweden classified by forensic pathologists as fatal drug poisonings (N = 6894) were retrieved from a toxicology database (TOXBASE) belonging to the National Board of Forensic Medicine. The deaths were further classified as suicides N = 2288 (33%), undetermined N = 2260 (33%) and accidental N = 2346 (34%). The average age (± SD) of all victims was 49.1 ± 15.9 years and men 47.4 ± 15.6 years were 5-year younger than women 52.2 ± 15.8 years (p < 0.01). Most of the deceased (78%) were poly-drug users although a single drug (mono-intoxications) was found in 22% of all poisoning deaths (p < 0.001). The number of drugs in blood samples varied from 1 to 12 with a median of 3-4 per case. Mono-intoxication deaths were mostly ethanol-related (N = 976) and the mean and median blood-alcohol concentration (BAC) was 3.06 g/L and 3.10 g/L, respectively. The BAC decreased as the number of additional drugs in blood increased from 2.15 g/L with one drug to 1.25 g/L with 6 or more drugs. The mean (median) concentrations of non-alcohol drugs in mono-intoxication deaths were morphine (N = 93) 0.5mg/L (0.2mg/L), amphetamine (N = 39) 2.0mg/L (1.2mg/L), dextropropoxyphene (N = 33) 3.9 mg/L (2.9 mg/L), dihydro-propiomazine (N = 32) 1.6 mg/L (1.0mg/L) and 7-amino-flunitrazepam (N = 28), 0.4 mg/L (0.3mg/L). Elevated blood morphine in these poisoning deaths mostly reflected abuse of heroin as verified by finding 6-monoacetyl morphine (6-MAM) in the blood samples. When investigating drug poisoning deaths a comprehensive toxicological analysis is essential although the results do not reveal the extent of prior exposure to drugs or the development of pharmacological tolerance. The concentrations of drugs determined in post-mortem blood are one element in the case. The autopsy report, the police investigation, the findings at the scene and eye-witness statements should all be carefully considered when the cause and manner of death are determined.

Forensic toxicology

Forensic toxicology has developed as a forensic science in recent years and is now widely used to assist in death investigations, in civil and criminal matters involving drug use, in drugs of abuse testing in correctional settings and custodial medicine, in road and workplace safety, in matters involving environmental pollution, as well as in sports doping. Drugs most commonly targeted include amphetamines, benzodiazepines, cannabis, cocaine and the opiates, but can be any other illicit substance or almost any over-the-counter or prescribed drug, as well as poisons available to the community. The discipline requires high level skills in analytical techniques with a solid knowledge of pharmacology and pharmacokinetics. Modern techniques rely heavily on immunoassay screening analyses and mass spectrometry (MS) for confirmatory analyses using either high-performance liquid chromatography or gas chromatography as the separation technique. Tandem MS has become more and more popular compared to single-stage MS. It is essential that analytical systems are fully validated and fit for the purpose and the assay batches are monitored with quality controls. External proficiency programs monitor both the assay and the personnel performing the work. For a laboratory to perform optimally, it is vital that the circumstances and context of the case are known and the laboratory understands the limitations of the analytical systems used, including drug stability. Drugs and poisons can change concentration postmortem due to poor or unequal quality of blood and other specimens, anaerobic metabolism and redistribution. The latter provides the largest handicap in the interpretation of postmortem results.

Postmortem toxicology

Results from toxicological analyses in death investigations are used to determine whether foreign substances were a cause of death, whether they contributed to death, or whether they caused impairment. Drug concentrations are likely to change during pre-terminal stages due to altered pharmacokinetics, to treatment during resuscitation or in the intensive care unit, to concomitant illness or to the presence of drug tolerance. The potential for postmortem changes must be considered in all but a few drugs. Formation of new entities as well as degradation of drugs may occur, especially in putrefied corpses; in addition, body fluids and tissues may be severely affected by autolysis and putrefaction. Specimens should be selected based on individual case history and on their availability. Analytical procedures should be performed in accordance with a proper quality assurance program for toxicological investigations. Problems are most likely to occur during the isolation and identification of a drug. Interpretation of analytical results is often limited by the inadequate information provided in a particular case.

Post-mortem clinical pharmacology

Clinical pharmacology assumes that deductions can be made about the concentrations of drugs from a knowledge of the pharmacokinetic parameters in an individual; and that the effects are related to the measured concentration. Post-mortem changes render the assumptions of clinical pharmacology largely invalid, and make the interpretation of concentrations measured in post-mortem samples difficult or impossible. Qualitative tests can show the presence of substances that were not present in life, and can fail to detect substances that led to death. Quantitative analysis is subject to error in itself, and because post-mortem concentrations vary in largely unpredictable ways with the site and time of sampling, as a result of the phenomenon of post-mortem redistribution. Consequently, compilations of 'lethal concentrations' are misleading. There is a lack of adequate studies of the true relationship between fatal events and the concentrations that can be measured subsequently, but without such studies, clinical pharmacologists and others should be wary of interpreting post-mortem measurements.

[Interest of post mortem analysis in diagnosis and etiopathogeny of ischemic myocardial infarction]

The discovery of an ischaemic myocardial infarction during forensic or scientific autopsy is sometimes surprising when found in a young subject. It is therefore important to find out the etiology of vascular lesions to take preventive measures in the family. In post mortem, some complementary analysis can be performed to determine the diagnosis of ischaemic myocardial infarction and its etiopathogeny. Such analyses, routinely made in forensic practice, are rarely used by pathologists during scientific autopsy. Some biological mediums are stable enough to be used for biological, biochemical and even genetical analyses. We will study the different post mortem analyses, and see their interest and reliability.

Demands on scientific studies in clinical toxicology

Scientific case studies in clinical toxicology on single cases or series of similar cases should document sufficient information on the clinical methodology and observations, the medical laboratory methodology and results, the toxicological analyses methodology and results, the source of used reference values for drug/poison concentrations and kinetics with critical discussion of such values, a description and discussion of the toxicodynamic, the toxicological and the kinetic properties of the detected drugs and/or poisons. The data management, statistical analysis and finally the clinical and/or analytical outcomes must also be described and discussed in correlation to already published data. Statistical methods used for evaluation of clinical as well as for analytical data should be described in detail. When possible, quantitative findings should be presented with appropriate indicators of measurement error or uncertainty. Requirements for such studies are discussed.

Interpreting results of ethanol analysis in postmortem specimens: A review of the literature

We searched the scientific literature for articles dealing with postmortem aspects of ethanol and problems associated with making a correct interpretation of the results. A person's blood-alcohol concentration (BAC) and state of inebriation at the time of death is not always easy to establish owing to various postmortem artifacts. The possibility of alcohol being produced in the body after death, e.g. via microbial contamination and fermentation is a recurring issue in routine casework. If ethanol remains unabsorbed in the stomach at the time of death, this raises the possibility of continued local diffusion into surrounding tissues and central blood after death. Skull trauma often renders a person unconscious for several hours before death, during which time the BAC continues to decrease owing to metabolism in the liver. Under these circumstances blood from an intracerebral or subdural clot is a useful specimen for determination of ethanol. Bodies recovered from water are particular problematic to deal with owing to possible dilution of body fluids, decomposition, and enhanced risk of microbial synthesis of ethanol. The relationship between blood and urine-ethanol concentrations has been extensively investigated in autopsy specimens and the urine/blood concentration ratio might give a clue about the stage of alcohol absorption and distribution at the time of death. Owing to extensive abdominal trauma in aviation disasters (e.g. rupture of the viscera), interpretation of BAC in autopsy specimens from the pilot and crew is highly contentious and great care is needed to reach valid conclusions. Vitreous humor is strongly recommended as a body fluid for determination of ethanol in postmortem toxicology to help establish whether the deceased had consumed ethanol before death. Less common autopsy specimens submitted for analysis include bile, bone marrow, brain, testicle, muscle tissue, liver, synovial and cerebrospinal fluids. Some investigators recommend measuring the water content of autopsy blood and if necessary correcting the concentration of ethanol to a mean value of 80% w/w, which corresponds to fresh whole blood. Alcoholics often die at home with zero or low BAC and nothing more remarkable at autopsy than a fatty liver. Increasing evidence suggests that such deaths might be caused by a pronounced ketoacidosis. Recent research has focused on developing various biochemical tests or markers of postmortem synthesis of ethanol. These include the urinary metabolites of serotonin and non-oxidative metabolites of ethanol, such as ethyl glucuronide, phosphatidylethanol and fatty acid ethyl esters. This literature review will hopefully be a good starting point for those who are contemplating a fresh investigation into some aspect of postmortem alcohol analysis and toxicology.