Interpretation of analytical toxicology results in life and at postmortem

Development and validation of headspace gas chromatography with a flame ionization detector method for the determination of ethanol in the vitreous humor

Introduction

Qualitative and quantitative testing of ethanol in post-mortem samples is an important analytical procedure that provides accurate, precise, and reliable results. Given the complexity of the issue, obtaining a realistic picture of lifelong alcoholemia requires supporting blood ethanol findings with analyses of alternative samples, primarily vitreous humor (VH).

Objective

The objective of this study was to develop and validate a headspace gas chromatography with flame ionization detection (HS/GC-FID) method for determining ethanol concentration in VH.

Materials and methods

Conditions for the HS/GC-FID method were established and the method was validated according to the guidelines of the European Medicines Agency. Validation parameters such as precision, accuracy, specificity, sensitivity, and linearity over a wide concentration range were evaluated through statistical analysis.

Results

The method demonstrated precision, accuracy, specificity, and sensitivity. Additionally, it proved to be linear across a wide concentration range and relatively fast, making it suitable for rapid and routine determination of ethanol concentration in VH, particularly for forensic applications.

Conclusion

Results from validation and application of the method to VH samples indicate that ethanol concentration in VH can be reliably determined using the presented HS/GC-FID method, making it a valuable tool in forensic investigations.

Tolerant or Intolerant? Learning From Studying Drug Concentrations in the Living and the Dead

A BSTRACT

Tolerance is the diminished response to a drug that occurs when that drug is repeatedly used, and the body adapts to its continued presence. This means that greater blood concentrations are required to achieve desired effects, produce impairment, or cause death. Without case-specific information, the pharmacodynamic impacts of a drug on an individual are difficult to ascertain based on its concentration alone. One starting point, however, is to compare reported findings with reference ranges associated with therapeutic, toxic, and lethal outcomes. Toxicologists have observed concentrations dramatically increase over time in the living population for some drugs to concentrations that can easily be associated with impairment and lethal outcomes. It is, therefore, important to continually monitor and be familiar with drug concentrations found in the living to interpret postmortem concentrations. To emphasize this approach, we compared fentanyl concentrations from JAN 2010 to OCT 2023 in individuals investigated for driving under the influence of drugs to postmortem cases. This comparison highlights the changing nature of tolerance, stresses the importance of not relying solely on reference ranges for result interpretations, and discusses the importance of the autopsy in identifying or ruling out other potential causes of death.

Ethanol concentrations in various biological specimens: Living and postmortem forensic toxicology analysis and comprehensive literature review

Alcohol use upsurges the risk for many chronic ill-health consequences such as hepatitis, malignancies, and disastrous outcomes like road traffic accidents ending in fatal injuries. Biochemical and toxicological analysis of different body fluids is crucial for identifying the cause of death and postmortem interval in many forensic cases. Blood, urine, and vitreous fluid are the most valuable body fluids for detecting alcohol during any toxicological analysis. Alcohol is responsible for widespread morbidity and mortality worldwide. Blood alcohol concentration (BAC) is a necessary toxicological test to investigate various crime and accident scenes. This study comprehensively explores the demographic characteristics, BAC distribution, and correlations of alcohol concentrations in postmortem and living cases. Postmortem cases (N = 166) reveal intriguing demographic patterns, with notable variations in year distribution, nationality, sex, age groups, occupation, smoking habits, place of death, and psychiatric history. Living cases (N = 483) exhibit distinct demographic profiles, emphasizing differences in year distribution, nationality, sex, age groups, and smoking habits. Analysis of BAC distribution reveals diverse patterns in both postmortem and living cases, providing valuable insights into the prevalence of different BAC levels in each group. Correlation analyses unveil strong associations between alcohol concentrations in various biological samples in postmortem cases, highlighting the interdependence of blood, vitreous, and urine alcohol concentrations. Conversely, living cases display a moderate positive correlation between blood and urine alcohol concentrations. Comparative analyses showcase significant differences in mean alcohol concentrations between postmortem and living cases, suggesting variations in alcohol metabolism and distribution. These findings underscore the importance of considering temporal factors in interpreting alcohol concentrations in forensic and clinical contexts. In conclusion, this study enhances our understanding of alcohol-related incidents by delineating demographic profiles, BAC distributions, and correlations between different biological samples. Such insights are crucial for refining investigative and clinical approaches, contributing to the broader fields of forensic science and public health.

A primary study of ethanol production in postmortem liver and muscle tissue of rats

OBJECTIVE

To study the characteristics of postmortem ethanol production and its relation with alcohol congeners in postmortem rat liver and muscle tissues.

METHOD

Postmortem liver and muscle tissues in Sprague-Dawley rats, from postmortem time interval (PMI) day 0-20, were analyzed via headspace gas chromatograph flame ionization detection to observe production of postmortem ethanol and 5 selected alcohol congeners.

RESULT

1. Putrid ethanol production increased gradually to a peak and then decreased with the prolongation of PMI; 2. Acetaldehyde, 1-propanol, and 3-methyl-butyraldehyde were produced along with postmortem ethanol; 1-butanol was only detected from day 11-20; 3. The concentrations of acetaldehyde, 1-propanol and 3-methyl-butyraldehyde was related with ethanol production. Fifteen mathematical models were constructed for putrid ethanol production based on acetaldehyde, 1-propanol, and 3-methyl-butyraldehyde.

CONCLUSION

A peak in postmortem ethanol production was identified. The production trends of acetaldehyde, 1-propanol, and 3-methyl-butyraldehyde in the liver, and of 1-propanol in muscle, were consistent with those of ethanol, and could potentially to be used as biomarkers of postmortem ethanol production. Further human samples and data analysis are needed to verify this.

Postmortem redistribution of cocaine and its metabolites, benzoylecgonine and ecgonine methyl ester in humans: Important variables that might be influencing the central blood / peripheral blood ratio

INTRODUCTION

A big challenge in forensic toxicology is the correct interpretation of the results of quantitative analyses in postmortem cases. Postmortem drug concentrations not necessarily reflect the drug concentrations at the time of death, due to postmortem changes in drug concentrations caused by postmortem redistribution (PMR). Cardiac blood is more prone to PMR related concentration changes than peripheral blood. Because of this difference in susceptibility to PMR related concentration changes, the ratio of cardiac blood concentration/peripheral blood concentration (C/P) of a drug is an often-used marker of PMR. In this study, we investigated the relationship between different potentially significant variables and the C/P ratios of cocaine, benzoylecgonine (BE) and ecgonine methyl ester (EME) in humans. The aim was to elucidate the mechanisms involved in PMR of these substances and potentially provide guidelines aiding forensic toxicologists in the interpretation of postmortem quantitative results of cocaine and its metabolites. To differentiate between postmortem concentration changes due to redistribution versus degradation of cocaine, the relationships between these variables and metabolite/cocaine ratios were investigated as well.

METHOD

Toxicological results of all postmortem cases that were positive for cocaine, BE and/or EME investigated by the Netherlands Forensic Institute between January 1st 2010 and July 31st 2020 were reviewed. The C/P ratios, BE/cocaine ratios and EME/cocaine ratios were determined for all selected cases. Cocaine, BE and/or EME were quantified in both femoral blood and cardiac blood in a total of 148 cases. Ratios were compared between subgroups by performing either a Mann-Whitney U test or a Kruskal-Wallis test followed by post-hoc Mann-Whitney U test.

RESULTS

A statistically significant difference in C/P ratio of EME was observed between trauma and non-trauma cases with median C/P ratios of 2.03 and 1.57, respectively (p value=0.001). A statistically significant difference in EME/cocaine ratio was observed between the BMI subgroups 18.5 - 25.0 kg/m2 and> 25 kg/m2 with median EME/cocaine ratios of 3.79 and 1.58, respectively (p-value<0.001).

CONCLUSION

Postmortem cocaine concentrations should be interpreted with caution, considering the occurrence of both PMR and postmortem degradation. When interpreting postmortem toxicological results in cocaine-related fatalities, it might prove useful to take the above-mentioned variables into account.

The Other Face of Insulin—Overdose and Its Effects

Insulin is the most effective glycemic-lowering drug, and for people suffering from type 1 diabetes it is a life-saving drug. Its self-dosing by patients may be associated with a higher risk of overdose, both accidental and deliberate. Insulin-induced hypoglycemia causes up to 100,000 emergency department calls per year. Cases of suicide attempts using insulin have been described in the literature since its introduction into therapy, and one of the important factors in their occurrence is the very fact of chronic disease. Up to 90% of patients who go to toxicology wards overdose insulin consciously. Patients with diabetes are burdened with a 2–3 times higher risk of developing depression compared to the general population. For this reason, it is necessary to develop an effective system for detecting a predisposition to overdose, including the assessment of the first symptoms of depression in patients with diabetes. A key role is played by a risk-conscious therapeutic team, as well as education. Further post-mortem testing is also needed for material collection and storage, as well as standardization of analytical methods and interpretation of results, which would allow for more effective detection and analysis of intentional overdose—both by the patient and for criminal purposes.

Modeling Postmortem Ethanol Production/Insights into the Origin of Higher Alcohols

The forensic toxicologist is challenged to provide scientific evidence to distinguish the source of ethanol (antemortem ingestion or microbial production) determined in the postmortem blood and to properly interpret the relevant blood alcohol concentration (BAC) results, in regard to ethanol levels at death and subsequent behavioral impairment of the person at the time of death. Higher alcohols (1-propanol, 1-butanol, isobutanol, 2-methyl-1-butanol (isoamyl-alcohol), and 3-methyl-2-butanol (amyl-alcohol)) are among the volatile compounds that are often detected in postmortem specimens and have been correlated with putrefaction and microbial activity. This brief review investigates the role of the higher alcohols as biomarkers of postmortem, microbial ethanol production, notably, regarding the modeling of postmortem ethanol production. Main conclusions of this contribution are, firstly, that the higher alcohols are qualitative and quantitative indicators of microbial ethanol production, and, secondly that the respective models of microbial ethanol production are tools offering additional data to interpret properly the origin of the ethanol concentrations measured in postmortem cases. More studies are needed to clarify current uncertainties about the origin of higher alcohols in postmortem specimens.

Monte Carlo optimization method based QSAR modeling of postmortem redistribution of structurally diverse drugs

The Monte Carlo optimization method was employed for the development of the QSAR model for the prediction for postmortem redistribution of structurally diverse drugs.

Postmortem redistribution of morphine in humans: Important variables that might be influencing the central blood/peripheral blood ratio

INTRODUCTION

In the field of forensic toxicology, many unexpected deaths are investigated as to whether toxicological substances may have caused or contributed to someone's death. One of the factors that makes interpretation of the results of quantitative analysis in postmortem toxicology challenging, is that measured postmortem drugs levels may vary according to the sampling site and the interval between death and specimen collection. These site- and time-dependent variations are caused by 'postmortem redistribution' (PMR). Literature shows that there are several factors that determine the degree of PMR, such as cell and tissue changes after death, decomposition and the physicochemical characteristics of drugs. Blood from peripheral sites seems to be less affected by PMR than cardiac blood. Therefore, the ratio of cardiac blood concentration/peripheral blood concentration (C/P) of a drug is often used as a marker of the extent of postmortem redistribution. In this study, we investigated the relationship between different potentially important variables and the C/P ratio of morphine in humans in order to provide new insights that might assist in the interpretation of quantitative results in forensic casework.

METHOD

Toxicological results of all morphine positive postmortem cases investigated by the Netherlands Forensic Institute between January 1, 2010 and July 31, 2020 were reviewed. Morphine was quantified in both femoral and cardiac blood in a total of 103 cases. The C/P ratios were determined for all selected cases. To collect data for this study, all corresponding files were reviewed. C/P ratios were compared between subgroups by performing either a Mann-Whitney U test or a Kruskal-Wallis test, followed by a post-hoc Mann-Whitney U test. Bonferroni correction was performed to correct for the likelihood of a significant result by chance due to multiple testing. After Bonferroni correction, a p-value< 0.004 was considered statistically significant.

RESULTS

The data suggests a relationship between grade of decomposition at autopsy, position of the corpse at discovery, route of administration, attempted resuscitation and the C/P ratio of morphine with p-values of 0.010, 0.026, 0.035 and 0.046, respectively.

CONCLUSION

Grade of decomposition at autopsy, position of the corpse at discovery, route of administration and attempted resuscitation seem to be influencing the C/P ratio of morphine. Of these four variables, the route of administration seems to have the greatest impact.

Modeling microbial ethanol production by S. aureus, K. pneumoniae, and E. faecalis under aerobic/anaerobic conditions - applicability to laboratory cultures and real postmortem cases

A quite intriguing subject being intensively researched in the forensic toxicology field is the source of postmortem determined blood ethanol concentration: antemortem ingestion or postmortem microbial production. Our previous research on microbial ethanol production has reported a quantitative relationship between the ethanol and the higher alcohols and 1-butanol produced by Escherichia coli, Clostridium perfrigens, and Clostridium sporogenes. In this contribution, we continue our research reporting on the following: (i) the patterns of ethanol, higher alcohols, and 1-butanol production by the microbes Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecalis (all being aerobic/facultative anaerobic species, common corpse's colonizers, and ethanol producers), under controlled laboratory conditions, (ii) the mathematical modeling, with simple mathematical equations, of the correlation between ethanol concentration and the other studied alcohols' concentrations, by performing multiple linear regression analysis of the results, and (iii) the applicability of the constructed models in microbial cultures developed under different temperature than that used to build the models, in denatured blood cultures and in real postmortem cases. The aforementioned alcohols were proved to be all indicators of ethanol production, both in qualitative and quantitative terms. 1-Propanol was the most significant alcohol in modeling microbial ethanol production, followed by methyl-butanol. The K. pneumoniae's models achieved the best scoring in applicability (E < 40%) compared to the S. aureus and E. faecalis models, both at laboratory microbial cultures at 37 °C and real postmortem cases. Overall, a noteworthy accuracy in estimating the microbial ethanol in cultures and autopsy blood is achieved by the employed simple linear models.

Critical Analysis of Laboratory Testing Methodologies When Interpreting Conflicting Results at Autopsy

ABSTRACT

Toxicological analysis is an important diagnostic component of a postmortem examination and may involve both antemortem and postmortem specimens. Here, we present a case in which an antemortem specimen, when reanalyzed in the forensic toxicology laboratory, resulted in values that contradicted the reported values from the medical record and required further investigation. This case involves a 51-year-old man decedent with a medical history of chronic alcohol abuse. His antemortem urine drug screen, performed upon admission to an emergency department, was negative. His serum blood alcohol level at presentation was reported as 0.960 g/dL and, repeated 4 hours later, was 0.500 g/dL with a comment indicating that there was significant lipemia interfering with the results. At autopsy, the antemortem blood sample collected from the hospital, postmortem blood, and vitreous humor samples were analyzed and all 3 samples were found to be negative for ethanol. The hospital laboratory used an enzymatic assay for ethanol detection, which is known to be impacted by lipemia, and the forensic laboratory used head-space gas chromatography, which is not impacted by lipemia. This highlights the need to critically analyze laboratory testing methodologies when interpreting conflicting results at autopsy.

Evaluation and review of ways to differentiate sources of ethanol in postmortem blood

Accurate determination of a person's blood alcohol concentration (BAC) is an important task in forensic toxicology laboratories because of the existence of statutory limits for driving a motor vehicle and workplace alcohol testing regulations. However, making a correct interpretation of the BAC determined in postmortem (PM) specimens is complicated, owing to the possibility that ethanol was produced in the body after death by the action of various micro-organisms (e.g., Candida species) and fermentation processes. This article reviews various ways to establish the source of ethanol in PM blood, including collection and analysis of alternative specimens (e.g., bile, vitreous humor (VH), and bladder urine), the identification of non-oxidative metabolites of ethanol, ethyl glucuronide (EtG) and ethyl sulfate (EtS), the urinary metabolites of serotonin (5-HTOL/5-HIAA), and identification of n-propanol and n-butanol in blood, which are known putrefaction products. Practical utility of the various biomarkers including specificity and stability is discussed.

Distinguishing between Contact and Administration of Heroin from a Single Fingerprint using High Resolution Mass Spectrometry

Fingerprints have been proposed as a promising new matrix for drug testing. In previous work it has been shown that a fingerprint can be used to distinguish between drug users and nonusers. Herein, we look at the possibility of using a fingerprint to distinguish between dermal contact and administration of heroin. Fingerprint samples were collected from (i) 10 patients attending a drug rehabilitation clinic, (ii) 50 nondrug users and (iii) participants who touched 2 mg street heroin, before and after various hand cleaning procedures. Oral fluid was also taken from the patients. All samples were analyzed using a liquid chromatography—high resolution mass spectrometry method validated in previous work for heroin and 6-AM. The HRMS data were analyzed retrospectively for morphine, codeine, 6-acetylcodeine and noscapine. Heroin and 6-AM were detected in all fingerprint samples produced from contact with heroin, even after hand washing. In contrast, morphine, acetylcodeine and noscapine were successfully removed after hand washing. In patient samples, the detection of morphine, noscapine and acetylcodeine (alongside heroin and 6-AM) gave a closer agreement to patient testimony on whether they had recently used heroin than the detection of heroin and 6-AM alone. This research highlights the importance of washing hands prior to donating a fingerprint sample to distinguish recent contact with heroin from heroin use.

Toxicological Investigation of Drug-Related Cases in Greece: Interpretation of Analytical Findings

The process of toxicological analysis of postmortem specimens can reveal some special difficulty compared to the clinically derived specimens. Many drugs are not stable and the chemical changes that occur in the specimens, due to the hydrolysis processing, the time passed, the drug metabolism, and matrix effect, even when the postmortem interval is short, may affect the interpretation of the toxicological results. This interpretation may be critical, not only to the thorough investigation of different kind of forensic cases, but also to clinical or other cases as it provides very significant challenges to the scientists. This article reviews (a) particular toxicological issues associated with some toxic substances responsible for common lethal or nonlethal poisonings, such as opiates, cannabis, and cocaine and the vast number of factors that affect drug concentration; and (b) focuses on toxicological issues associated with the analytical findings of certain postmortem specimens. The toxic substances cited in the present paper are the most commonly found in forensic cases in Greece. The investigation of these drug-related deaths has revealed that heroin, alone or in combination with other psychoactive substances, such as cannabis and cocaine, is the main drug involved in these deaths.

From Death to Death Certificate: What do the Dead say?

This is an overview of medicolegal death investigation and death certification. Postmortem toxicological analysis, particularly for ethanol and drugs of abuse, plays a large role in the forensic investigation of natural and unnatural deaths. Postmortem drug concentrations must be interpreted in light of the autopsy findings and circumstances. Interpretations of drug and ethanol concentrations are important for death certification, but they also may be important for other stakeholders such as police, attorneys, public health practitioners, and the next-of-kin.

Assessment of the Role Played by N-propanol Found in Postmortem Blood in the Discrimination Between Antemortem Consumption and Postmortem Formation of Ethanol Using Rats

This study disproves the reliability of n-propanol as a biomarker to establish whether the ethanol found in postmortem blood is derived from antemortem ingestion or postmortem putrefactive processes. Two groups of rats were given ethanol or normal saline solution, respectively, and sacrificed 1.5 h later. After putrefaction, blood and, in a few cases, urine samples from the rats were analyzed for ethanol and n-propanol by head-space gas chromatography equipped with flame ionization detection. Although the concentration ratios of ethanol/n-propanol in the postmortem blood collected from the bodies without prior alcohol consumption were expected to be <20 (as per limited case reports and previous in vitro studies), in samples from several rats that were on saline solution, this ratio was found to exceed 20. In conclusion, the concentration ratio of ethanol/n-propanol in postmortem blood does not allow for the discernment between antemortem ingestion and the postmortem synthesis of ethanol.

The postmortem redistribution of iso-α-acids in postmortem specimens

Iso-α-acids (IAA) and reduced IAA can be used as beer-specific ingredient congeners to confirm beer consumption when detected in blood and other specimens using a UHPLC-MS/MS method. Recent analysis of postmortem casework demonstrated a high prevalence of beer consumption and the possibility of providing the source of alcohol in forensic casework. Research outlined in this manuscript has examined the degree to which the interval after death and quality of blood affects the concentration of IAA in postmortem cases. Postmortem whole blood and serum were analyzed in cases where natural or reduced IAA groups were detected. The trans-IAA, cis-IAA, and tetrahydro-IAA (TIAA) groups were subject to postmortem redistribution, although only weakly associated with the length of time from death to collection of specimens. Serum had threefold higher concentrations than blood for trans-IAA, cis-IAA, and TIAA. These studies confirm that although postmortem concentrations cannot be easily compared to concentrations found in living persons the presented findings do provide some understanding to assist in interpretation where the confirmation of beer consumption is required in forensic casework.

Modern analytical technologies for the detection of drug abuse and doping

Consequences to individuals convicted of abusing prohibited drugs or doping agents can be severe, including loss of employment, child custody, driving privileges, right to compete in international sports and ultimately freedom, when mandatory confinement occurs. In view of these penalties, laboratories charged with providing evidence must maximize testing accuracy. False positive and false negative tests are prevented by combining sensitive immunoassays and specific chromatographic-mass spectrometric detection. In addition, testing different biological matrices offers unique information about the drug-use history of an individual.:

Applying quantitative structure-activity relationship (QSAR) methodology for modeling postmortem redistribution of benzodiazepines and tricyclic antidepressants

Postmortem redistribution (PMR) constitutes a multifaceted process, which complicates the interpretation of drug concentrations by forensic toxicologists. The present study aimed to apply quantitative structure-activity relationship (QSAR) analysis for modeling PMR data of structurally related drugs, 10 benzodiazepines and 10 tricyclic antidepressants. For benzodiazepines, an adequate QSAR model was obtained (R(2) = 0.98, Q(2) = 0.88, RMSEE = 0.12), in which energy, ionization and molecular size exerted significant impact. For tricyclic antidepressants, an adequate QSAR model with slightly inferior statistics (R(2) = 0.95, Q(2) = 0.87, RMSEE = 0.29) was established after exclusion of maprotiline, in which energy parameters, basicity character and lipophilicity exerted significant contribution. Thus, QSAR analysis could be used as a complementary tool to provide an informative illustration of the contributing molecular, physicochemical and structural properties in PMR process. However, the complexity, non-static and time-dependent nature of PMR endpoints raises serious concerns whether QSAR methodology could predict the degree of redistribution, highlighting the need for animal-derived PMR data.

Children intoxications: what is abuse and what is not abuse

The curiosity and the natural tendency to explore the environment put young children at an increased risk of poisoning over older children and adults. Poisonings are a significant area of concern from 1 year of age and progressively contribute more to overall rates of morbidity and mortality until children reach adulthood. Particularly, the abuse of children by poisoning is also highly common with thousands of fatalities. A practical strategy is presented that aims to alert health, forensic, and law enforcement professionals to this problem and to demystify the preconception that it is a rare form of abuse or neglect. Compounds that are foreign to a living organism (xenobiotics) and those present within body (endobiotics), mainly involved in children intoxications and contextual examples related to exposure are also reviewed. Particular concern is given to concepts in the field of children poisoning. The described history and the clinical and toxicological evaluation are discussed, and harmonized protocols regarding correct procedures for sample collection to forensic toxicological analysis are proposed. Since children are particularly vulnerable to the toxic effects of high doses of xenobiotics and endobiotics, special consideration on the preparation of the environment that surrounds children in order minimize all possible risks will be also considered.

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.

Simultaneous quantification of morphine and cocaine in hair samples from drug addicts by GC-EI/MS

The development of analytical techniques that enable the use of hair as an alternative matrix for the analysis of drugs of abuse is useful for confirming the exposure in a larger time window (weeks to months, depending on the length of the hair shaft). In the present study a methodology aimed at the simultaneous quantification of cocaine and morphine in human hair was developed and validated. After decontamination, hair samples (20 mg) were incubated with a mixture of methanol/hydrochloric acid (2:1) at 65 °C overnight (~16 h) in order to extract the drugs of the matrix. Purification was performed by solid-phase extraction using mixed-mode extraction cartridges. After derivatization with N-methyl-N-(trimethylsilyl) trifluoroacetamide, blank, standards and samples were analyzed by gas chromatography/electron impact-mass spectrometry (GC-EI/MS). The method proved to be selective, as there were no interferences of endogenous compounds with the same retention time as cocaine, morphine and ethylmorphine (internal standard). The regression analysis for both analytes showed linearity in the range 0.25-10.00 ng/mg with correlation coefficients ranging from 0.9989 to 0.9991. The coefficients of variation oscillated between 0.83 and 14.60%. The limits of detection were 0.01 and 0.02 ng/mg, and the limits of quantification were 0.03 and 0.06 ng/mg for cocaine and morphine, respectively. The proposed GC-EI/MS method provided an accurate and simple assay with adequate precision and recovery for the quantification of cocaine and morphine in hair samples. The proof of applicability was performed in hair samples obtained from drug addicts enrolled in a Regional Detoxification Treatment Center. The importance of hair samples is highlighted, since positives results were obtained when urine immunoassay analyses were negative.

Postmortem drug levels: innocent bystander or guilty as charged

Determining the etiology or cause of an event in forensic cases often creates many theories. On piece of additional information which may be helpful in cases involving a drug or medication are concentrations or serum levels. Although many confounders can affect the interpretation of the drug level, it is imperative to also relate the data to the clinical scenario presented. Drug levels can be highly variable, depending on the time drawn, location from where the sample was obtained, and reference/references utilized in its interpretation. Postmortem drugs levels often do not reflect the blood levels before death. A drug level can be elevated exclusively because of postmortem distribution. This may result in a conclusion of a poisoning as the cause of death when in fact the death resulted from nonpharmacologic or nontoxicologic causes. Caution is advised from making any conclusions based solely on the drug level; rather an in-depth review of the clinical scenario, reference literature, and drug characteristics are required.

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.

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.

Fatal toxicity of drugs used in psychiatry

Certified deaths from fatal poisoning (accidents, suicides and open verdicts) in England and Wales have declined steadily (from 3952 in 1979 to 2565 in 2004). There was also a small annual reduction in suicides in males and in females over this period. In 2004, self-poisoning accounted for 25% of suicides and open verdicts in males (n = 862) and 45% in females (n = 540). Poisoning death rates per million prescriptions were about 10 times higher for tricyclic antidepressants (TCAs) than for selective serotonin reuptake inhibitors (SSRIs), England and Wales, 1993-2004. However, despite the increased prescription of SSRIs and related compounds in recent years, there has been only a slight decrease (some 10%) in the annual number of antidepressant-related poisoning deaths, in line with the reduction in suicides (all methods) over this period. Citalopram appears to have higher overdose toxicity than other SSRIs. Of newer non-SSRI antidepressants, the overdose toxicity of venlafaxine, although lower than that of TCAs, appears to be higher than that of SSRIs, with seizures, serotonin syndrome, rhabdomyolysis, renal failure and hepatic failure having been reported. Poisoning deaths involving antipsychotics either alone, or with other drugs and/or alcohol are many fewer than those involving antidepressants (713 and 5602 deaths, respectively, England and Wales, 1993-2004). Following the restriction on thioridazine usage (2000), thioridazine-associated fatal poisoning fell to zero by 2002, but this was balanced by an increase in deaths associated with atypical antipsychotics, most notably clozapine, olanzapine and quetiapine. Antipsychotic-related poisoning deaths were higher in 2004 than at any time since 1993.

Requirements for bioanalytical procedures in postmortem toxicology

The application of analytical techniques in postmortem toxicology is often more difficult than in other forms of forensic toxicology owing to the variable and often degraded nature of the specimens and the diverse range of specimens available for analysis. Consequently, analysts must ensure that all methods are fully validated for the particular postmortem specimen(s) used. Collection of specimens must be standardized to minimize site-to-site variability and should if available include a peripheral blood sample and at least one other specimen. Urine and vitreous humor are good specimens to complement blood. In some circumstances solid tissues such as liver are recommended as well as gastric contents. Substance-screening techniques are the most important element since they will determine the range of substances that were targeted in the investigation and provide initial indication of the possible role of substances in the death. While immunoassay techniques are still commonly used for the most common drugs-of-abuse, chromatographic screening methods are required for general unknown testing. These are still predominately gas chromatography (GC) based using nitrogen/phosphorous detection and/or mass spectrometry (MS) detection, although some laboratories are now using time-of-flight MS or liquid chromatography (LC)-MS(MS) to cover a sometimes more limited range of substances. It is recommended that laboratories include a second chromatographic method to provide coverage of acidic and other substances not readily covered by a GC-based screen when extracts do not include all physiochemical types. This may include a gradient high-performance liquid chromatography (HPLC) photodiode array method, or better LC-MS(MS). Substance-specific techniques (e.g., benzodiazepines, opiates) providing a second form of identification (confirmation) are now divided between GC-MS(MS) and LC-MS(MS) procedures. LC-MS(MS) has taken over from many methods for the more polar compounds previously used in HPLC or in GC methods requiring derivatization. Analysts using LC-MS will need to obtain clean extracts to avoid poor and variable sensitivity caused by background suppression of the signal. Isolation techniques in postmortem toxicology tend to favor liquid extraction; however solid-phase extraction and solid-phase microextraction methods are available for many analytes.

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.

Urine as a Biological Specimen for Forensic Analysis of Alcohol and Variability in the Urine-to-Blood Relationship

This article concerns the use of urine as a biological specimen for determination of alcohol in clinical and forensic toxicology and discusses factors that might influence variability in the urine/blood concentration ratio of alcohol. A large number of human drinking experiments were conducted to determine the time course of urine-alcohol concentrations (UAC) in relation to blood-alcohol concentrations (BAC). The UAC and BAC curves were shifted in time and the BAC curve always began to decrease before the UAC started to decline. During the early absorption phase the UAC/BAC ratio was less than unity, whereas in the late absorption/distribution period the ratio was between 1.0-1.2. On reaching the post-absorptive phase, the UAC always exceeded BAC and UAC/BAC ratios averaged 1.3-1.4, increasing appreciably as BAC decreased towards zero. Alcohol-induced diuresis was most pronounced during the rising portion of the BAC curve and near to the peak value. After about 2 hours post-drinking, the production rate of urine diminished to the pre-drinking rate of about 0.5-1 mL/min. Drinking water during the post-absorptive phase of the alcohol curve produced dilute urine, as reflected in lower creatinine content and osmolality, although the concentration of ethanol remained unchanged. After subjects drank a moderate dose of ethanol (0.54-0.85 g/kg) about 2% of the dose was recoverable in the urine after 7 hours. Ethyl glucuronide, a minor metabolite of ethanol, was measured in urine samples from drunk drivers. The UAC/BAC ratio of ethanol in drunk drivers did not depend on the creatinine content of the urine and therefore the relative dilution of the specimens. When alcohol-free urine was spiked with glucose and infected with the yeast species Candida albicans, ethanol was produced by fermentation after approximately 24 hours storage at room temperature. This post-sampling synthesis of ethanol was prevented by sodium fluoride (1% weight by volume) in the urine tubes or by keeping the specimens in the cold (4 degrees C). The UAC and BAC were highly correlated (r > 0.95) in drunk drivers and in autopsy cases, although the residual standard deviations were appreciable. This speaks against attempting to estimate BAC indirectly from UAC in any individual case. The UAC/BAC ratio and the change in UAC between two successive voids can help to resolve whether a large amount of alcohol had recently been consumed. This information is useful to support or challenge allegations of drinking alcohol after driving, which has become known as the hip-flask defence.

Analytical Toxicology

The reliability and relevance of any analytical toxicology result is determined in the first instance by the nature and integrity of the specimen(s) submitted for analysis. This article provides guidelines for sample collection, labelling, transport and storage, especially regarding specimens obtained during a postmortem examination. Blood (5 mL) should be taken from two distinct peripheral sites, preferably left and right femoral veins, taking care not to draw blood from more central vessels. Urine (if available), vitreous humour (separate samples from each eye), a representative portion of stomach contents, and liver (10-20 g, right lobe) are amongst other important specimens. A preservative (sodium fluoride, 0.5-2% weight by volume (w/v) should be added to a portion of the blood sample/the sample from one vein, and to urine. Leave a small (10-20% headspace) in tubes containing liquids if they are likely to be frozen. Precautions to minimise the possibility of cross-contamination of biological specimens must be taken, especially if volatile poison(s) may be involved. If death occurred in hospital, any residual antemortem samples should be sought as a matter of urgency. Hair/nail collection should be considered if chronic exposure is suspected, for example, in deaths possibly related to drug abuse. A lock of hair the width of a pen tied at the root end is required for a comprehensive drug screen. The value of providing as full a clinical/occupational/circumstantial history as possible together with a copy of the postmortem report (when available) and of implementing chain-of-custody procedures when submitting samples for analysis cannot be over-emphasised.