Microbial degradation products of lurasidone and their significance in postmortem toxicology

Recent research reported that lurasidone degrades in unpreserved ante-mortem human whole blood inoculated with microorganisms known to dominate postmortem blood specimens. In vitro degradation occurred at a similar rate to risperidone, known to degrade in authentic postmortem specimens until below analytical detection limits. To identify the lurasidone degradation products formed, an Agilent 6520 liquid chromatograph quadrupole-time-of-flight mass spectrometer (LC-QTOF-MS) operating in auto-MS/MS mode was used. Numerous degradation products not previously reported in prior in vitro or in vivo pharmacokinetic studies or forced degradation studies were detected. Accurate mass data, mass fragmentation data, acetylation experiments, and a proposed mechanism of degradation analogous to risperidone supports initial identification of the major degradation product as N-debenzisothiazole-lurasidone (calculated m/z [M + H]⁺ = 360.2646). A standard was unavailable to conclusively confirm this identification. Retrospective data analysis of postmortem cases involving lurasidone identified the presence of the major degradation product in four of six cases where lurasidone was also detected. This finding is significant for toxicology laboratories screening for this drug in postmortem casework. The major postmortem lurasidone degradation product has consequently been added to the LC-QTOF-MS drug screen at Forensic Science SA (FSSA) to indicate postmortem lurasidone degradation in authentic postmortem blood specimens and as a marker of lurasidone administration in the event lurasidone is degraded to concentrations below detection limits.     

Vitreous humor in the evaluation of postmortem blood ethanol concentrations

Many studies have been published comparing blood (B) ethanol (EtOH) and vitreous humor (VH) EtOH concentrations. We conducted a similar study of routinely collected specimens to determine (1) whether the reported average VH/B ratios are consistent, (2) the percentage of cases with VH/B ratios outside of the expected range, and (3) the magnitude of B EtOH that can be associated with negative VH EtOH (less than 0.01 g/dL). VH EtOH less than 0.01 g/dL was associated with 41 specimens; 34 specimens had B EtOH less than 0.03 g/dL while a B EtOH as high as 0.12 g/dL was measured. For B EtOH less than 0.10 g/dL, 67% had VH EtOH within 0.02 g/dL of B EtOH (N = 101). For B EtOH greater than or equal to 0.10 g/dL, the VH/B EtOH ratio ranged from 0.10 to 1.91; the mean ratio was 1.17 and the median ratio was 1.18 (N = 205); and 64% had a ratio between 1.00 and 1.39. Vitreous humor can be used to facilitate understanding the significance of postmortem blood EtOH concentrations.     

Postmortem drug analysis: analytical and toxicological aspects

Publications focusing on the analysis of postmortem specimens for the presence of drugs were reviewed with particular reference to systematic toxicological analysis. Specimens included blood, liver, other solid specimens, and fly larvae. Extraction techniques published during the past 10 years most commonly used traditional solvent extraction techniques. High-performance liquid chromatography coupled to multichannel wavelength detection was most commonly used, which would easily lend itself to liquid chromatography-mass spectrometry. There were few practical differences in the assays validated for a range of postmortem specimens to those in other forms of forensic toxicology, unless substantially decomposed tissue was used. When putrefied specimens were analyzed, a back-extraction or other form of specimen cleanup was recommended to reduce interfering substances. Many immunoassays designed for urine have been adapted for use in blood and tissue homogenates. Immunoassays designed for blood analysis, however, are likely to have more useful cutoff values than immunoassays optimized for urine testing. Postmortem specimens provide less stability for a number of drugs than other types of specimens. This is particularly a problem for cocaine, heroin, and some antidepressants, antipsychotics, and benzodiazepines. A number of artifacts occur postmortem, which affects the concentration of drug in specimens. This includes postmortem redistribution for drugs with a high tissue concentration relative to blood. Consequently, the likely extent of any change in concentration is relevant to the interpretation of doses and drug effects.     

Further evidence for the presence of GHB in postmortem biological fluid: implications for the interpretation of findings

Analysis and interpretation of the findings for the drug of abuse gamma hydroxybutyric acid (GHB) in fatalities has become very problematic. This is primarily because of variable data in postmortem biological fluids resulting from the endogenous nature of the compound, possible postmortem production, and varying methods of detection. Preliminary studies support the use of plasma standards in determining urinary GHB concentrations and indicate measurement of GHB in postmortem biological fluids may be dependent on the method of analysis. In order to assist interpretation of postmortem data based on gas chromatography-mass spectrometry (GC-MS) analysis using GHB-d6 internal standard, the results of GHB concentrations measured routinely in postmortem blood and urine specimens in 40 fatalities received during a three-month period are shown. In all cases, GHB was not implicated in the cause of death; there was no apparent correlation between manner of death and resultant GHB concentrations. Mean concentrations of GHB determined in postmortem blood were found to be 12.3 mg/L (range = 2-29 mg/L, n = 38) and 12.6 mg/L (range = 4-25 mg/L, n = 17) (unpreserved and sodium fluoride-preserved samples, respectively) and 5.5 mg/L in unpreserved urine (range 0-18 mg/L, n = 39) and 4.8 mg/L in sodium fluoride-preserved (range 0-10 mg/L, n = 15) urine samples. Vitreous humor was available in two of the cases analyzed (GHB = 1 and 3 mg/L). The data support the potential use of sodium fluoride-preserved samples for interpretation of GHB concentrations, particularly if there has been an extended postmortem interval. In addition, interpretative cut-offs can be proposed for both postmortem blood and urine, based on the specific GC-MS method used. At blood concentrations less than 30 mg/L and at urine concentrations less than 20 mg/L, it is possible that any GHB detected could represent only endogenous GHB production.     

MDMA and MDA concentrations in antemortem and postmortem specimens in fatalities following hospital admission

Over the last 15 years, numerous deaths involving "Ecstasy" (3,4-methylenedioxymethamphetamine, MDMA) have been reported and described in the literature. In most cases, either antemortem or postmortem concentration data are available. Because of the wide range of results and potential idiosyncratic nature of MDMA toxicity, interpretation of both antemortem and postmortem concentrations is difficult. The possible influence of postmortem redistribution may be an overlooked factor, but existing data involve postmortem concentrations from varying anatomical sites. However, this paper describes for the first time an evaluation of the concentrations of MDMA and 3,4-methylenedioxyamphetamine (MDA) found in five fatalities admitted to hospital where both antemortem and postmortem blood samples were available. Admission MDMA and MDA concentrations ranged between 0.55 and 4.33 mg/L and 0 and 0.10 mg/L, respectively, in antemortem serum/plasma. Postmortem blood MDMA and MDA concentrations ranged between 0.47 and 28.39 mg/L and 0.02 and 1.33 mg/L, respectively. Postmortem concentrations were higher than corresponding antemortem concentrations in all 5 cases with postmortem/antemortem ratios between 1.1 and 6.6 for MDMA and 1.5 and 13.3 for MDA. Differences in concentrations were also observed between anatomical sites, with central sites (e.g., heart) having much higher concentrations than peripheral sites (e.g., femoral). Overall, MDMA and MDA appear to exhibit postmortem redistribution and concentrations measured in postmortem specimens (even from peripheral sites) are not directly comparable with antemortem findings close to or prior to death.     

Postmortem redistribution of two antipsychotic drugs, haloperidol and thioridazine, in the rat

Antipsychotic drugs may be associated with arrhythmia, ventricular fibrillation, or torsades de pointes, which can result in sudden death. These drugs could therefore be found in postmortem toxicological analyses of autopsy specimens following unexplained sudden death. The drug concentrations in tissues and body fluids change between the death and postmortem specimens collection because of postmortem redistribution. For this reason, it is often difficult to interpret the postmortem analysis. The aim of this study was to investigate postmortem redistribution of the two cardiotoxic antipsychotic drugs, haloperidol and thioridazine, in order to interpret the postmortem analysis. We have chosen the rat as an animal model. The rats received 1 mg/kg of haloperidol and 5 mg/kg of thioridazine by intraperitoneal injection. They were sacrificed and left at room temperature for 2, 6, 12, 24, or 48 h, at which times blood and tissue samples were taken. The drug analyses in tissues and blood were done using a liquid chromatography- tandem mass spectrometry method. Our results show that there is a redistribution of the two drugs from the lung to the cardiac blood. The concentration of the antipsychotic drugs in the lung decreased rapidly, whereas in the cardiac blood, this concentration increased within the first 2 h postmortem. By 48 h after death, the concentrations of the antipsychotic drugs were about twice as high as the initial concentrations in the cardiac blood. For the lungs, a decrease of 50% was observed between 0 and 48 h. Only myocardium and muscle concentrations did not change with the postmortem delay.     

Case studies of postmortem quetiapine: therapeutic or toxic concentrations?

The focus of this study was to determine if the analysis of a variety of postmortem biological specimens would aid in the toxicological interpretation of quetiapine in the cause and manner of death determinations. Postmortem quetiapine concentrations were examined in 21 medical examiner cases using liquid-liquid extraction and high-performance liquid chromatography analysis. Specimens analyzed were peripheral blood, central blood, liver, vitreous humor, and gastric contents, when available. Findings from this study suggest that therapeutic postmortem quetiapine concentrations may be less than 1 mg/L in both peripheral and central blood, less than 0.5 mg/L in vitreous, and less than 5 mg/kg in liver. Quetiapine concentrations indicative of toxicity were estimated at greater than 1 mg/L in peripheral and central blood, greater than 0.5 mg/L in vitreous, and greater than 5 mg/kg in the liver. Liver concentrations appeared to be particularly helpful in determining the potential for toxicity when compared with blood concentrations. Cases in which quetiapine was determined to play a significant role in the death indicated postmortem liver concentrations greater than 5 mg/kg. Cases in which quetiapine concentrations were considered incidental or noncontributory in the death had liver concentrations 2 mg/kg or less.     

Comparative alcohol concentrations in blood and vitreous fluid with illustrative case studies

The Toxicology Bureau of the New Mexico Department of Health performs drug and alcohol testing on approximately 2800 medical examiner cases each year across the entire state. Although blood is usually the preferred specimen for alcohol analysis, the importance of multiple specimen analysis in alcohol-related death investigation is well understood. Quantitative alcohol determination in a variety of postmortem specimens may provide important interpretive information. In a total of 322 consecutive cases, blood and vitreous alcohol concentrations were compared. No alcohol was detected in either specimen in only 27 of the cases. In the remaining 295 investigations, alcohol was detected in the vitreous fluid, blood, or both. Analysis of the data and presentation of case studies reinforce the need for multiple specimen analysis in alcohol-related death investigation. Postmortem blood and vitreous alcohol concentrations were compared in a series of 295 alcohol-positive cases. The vitreous alcohol concentration (VAC) exceeded the blood alcohol concentration (BAC) in 209 cases (71%). Blood alcohol concentrations exceeded vitreous concentrations in 81 cases (27%), and the concentrations were equivalent in 5 cases (2%). For the purpose of this study, samples that were negative in both specimens were excluded. In casework where the VAC > BAC, linear regression analysis indicated an R2 value of 0.958 (n = 209) and a VAC approximately 16% higher than the BAC. The VAC/BAC ratio was more variable at lower BACs (< 0.1 g/100 mL). The source of blood for this data set was predominantly femoral (n = 203), followed by heart (n = 5) and pleural cavity (n = 1). Although VAC/BAC ratios were more consistent at concentrations of 0.1 g/100 mL and above, the overall ratio ranged from 1.01 to 2.20. Of the 81 cases where BAC > VAC, a total of 24 cases indicated no vitreous alcohol. The range of blood alcohol concentrations among these cases was widely variable (0.01 to 0.30 g/100 mL). Unlike the VAC/BAC data set which consisted of 97% femoral blood, the source of blood in the BAC > VAC data set was slightly more variable. Of the 81 cases where BAC > VAC the blood source consisted of femoral (n = 68), heart (n = 8), pleural cavity (n = 2), carotid (n = 1), jugular (n = 1), and chest blood (n = 1). All analyses were conducted using dual-column gas chromatography with flame-ionization detection (GC-FID) with a reporting limit of 0.01 g/100 mL ethanol in postmortem samples. A series of case studies are used to demonstrate postmortem interpretive issues and the benefits associated with multiple specimen analysis. Cases include postmortem production of ethanol, rapid or unexpected death during the absorptive phase, and site-dependent differences following traumatic injury. Actual case studies involving other volatile organic compounds are also presented including isopropanol and acetone from endogenous and exogenous sources. Many of these cases studies highlight the difficulty associated with postmortem alcohol interpretation in the absence of multiple specimens or adequate case history.     

Postmortem digoxin-like immunoreactive substances (DLIS) in patients not treated with digoxin

Endogenous digoxin-like immunoreactive substances (DLIS) cross-react in immunoassays of digoxin. The postmortem rise in digoxin levels in patients treated with the drug may be due to its redistribution. It is unclear what is the contribution of DLIS to this increase and whether DLIS are present postmortem in patients not treated with digoxin. The objectives of this study were to determine whether DLIS are present after death in patients not treated with digoxin, whether a postmortem increase in DLIS is detectable and whether sampling site can affect DLIS concentrations. DLIS (measured as digoxin, TDx Abott) were determined in blood samples drawn antemortem from ICU patients; postmortem samples from femoral artery and cardiac chambers were taken at least 12 h after the death of these same patients. DLIS concentrations > or = 0.2 ng/ml were measured in 44 and 40% of patients antemortem and postmortem (femoral), respectively. No difference was found in DLIS levels between antemortem and postmortem femoral and cardiac samples. Age, ICU stay and postmortem sampling time did not affect the postmortem increase in DLIS. None of the levels was in the toxic range. DLIS may be present after death and their concentration does not increase postmortem. The interpretation of postmortem digoxin concentrations that fall in the therapeutic range should be done cautiously; such measurable levels do not necessarily indicate misuse or malicious intent even in patients who had not been treated with the drug.     

Evaluation of the methods used for carboxyhemoglobin analysis in postmortem blood

Numerous methods have been described in the literature for the determination of carboxyhemoglobin (COHb) in whole blood. The most popular and widely used have been (1) the spectrophotometric methods, which could be performed either by using a conventional spectrophotometer or by using specialized automated instruments known as CO-oximeters; (2) the gas chromatographic methods, with variable detection systems, which have been considered as the reference methods for every carbon monoxide analysis. The authors have critically reviewed previously reported comparative studies on these methods, considering statistical and analytical matters, in order to propose the best method for the determination of COHb in postmortem blood, that could be utilized in forensic toxicology laboratories where such analyses are limited in number (less than 20 per year). Criteria for evaluation have been accuracy, reliability, simplicity, time, and cost. The authors' concluding statement has been that the manual spectrophotometric method could be the method of choice for COHb determination in postmortem blood samples. It is simple, rapid, and reliable and fulfills the forensically acceptable accuracy. It is performed by the use of a conventional spectrophotometer, which is considered a basic instrument in every analytical laboratory.     

Three cases of fatal paramethoxyamphetamine overdose

Two recent cases of death due to paramethoxyamphetamine (PMA), a methoxylated phenylethylamine derivative, are described and compared with a previous PMA death that occurred in this province in 1985. The deceased were 18 or 19 years of age and were reported to have ingested either methylenedioxymethamphetamine (MDMA, Ecstasy) or methylenedioxyamphetamine (MDA) prior to their deaths. Concentrations of PMA were measured in both peripheral and heart blood samples using gas chromatography equipped with a nitrogen-phosphorus detector. PMA results in the most recent cases were 0.6 mg/L and 1.3 mg/L in the peripheral blood samples, and corresponding heart blood samples were 0.7 mg/L and 2.3 mg/L, respectively. In the 1985 case, the femoral blood concentration was 0.6 mg/L, and the heart blood concentration was 0.8 mg/L. Significant differences between heart and peripheral blood concentrations were observed in two of the three cases, which may indicate the potential for postmortem redistribution of PMA.     

Postmortem blood ketamine distribution in two fatalities

Despite the reported increased use of ketamine as a recreational drug, relatively few fatalities attributed to ketamine poisoning have been documented. Two recent fatalities in which ketamine was detected are described and compared with cases previously reported in the scientific literature. Concentrations of ketamine were measured in the heart and femoral blood samples using gas chromatography with nitrogen phosphorus detection. Ketamine concentrations in a 26-year-old man whose death was attributed to ketamine intoxication were 6.9 and 1.8 mg/L in heart and femoral blood, respectively. In this case, the ketamine concentration detected in the heart blood is in agreement with the lowest concentration reported in the literature, in which ketamine intoxication was ruled as the cause of death and no other drugs were present. Ketamine concentrations in a 20-year-old man, whose death was attributed to asthma and ketamine was considered an incidental finding, were 1.6 and 0.6 mg/L in heart and femoral blood, respectively. Marked differences between heart and femoral blood ketamine concentrations were observed in both of the reported cases. This may be indicative of incomplete distribution prior to death and/or postmortem redistribution of ketamine.     

Elevated postmortem ethanol concentrations in an insulin-dependent diabetic

A 54-year-old woman (165 cm, 37 kg) was found dead in her home during a welfare check after not having been seen for at least three days. The body showed clear evidence of decomposition. Her head was in what appeared to be a pool of blood. The residence was clean, neat, and showed no evidence of violence. Insulin was found in the refrigerator, and syringes were in the kitchen cabinet. In agreement with these physical findings, her clinical history indicated that she suffered insulin-dependent diabetes mellitus. Autolytic changes were noticed at autopsy, and no obvious cause of death was demonstrated. The autopsy heart blood sample screened negative for cocaine and/or metabolite (benzoylecgonine), phenethylamines, opiates, and barbiturates by radioimmunoassay. The alcohol concentration was 0.51 g/dL in the blood, 0.04 g/dL in the brain, 0.08 g/dL in the liver, and 0.05 g/dL in the urine, and acetone levels were 42 mg/dL, 53 mg/dL, 14 mg/dL, and 19 mg/dL, respectively. Isopropanol was also present in all samples analyzed. The cause of death was ruled as metabolic acidosis due to diabetes mellitus. Possible bacterial postmortem production of ethanol is considered as an explanation for the increased concentration of ethanol found in the postmortem heart blood.     

Fatal poisoning with a new phenylethylamine: 4-methylthioamphetamine (4-MTA)

There has been much publicity in the United Kingdom regarding a new phenylethylamine-based compound called 4-methylthioamphetamine (4-MTA), also known as para-methylthioamphetamine (p-MTA), MTA or "Flatliner". Chemically, 4-MTA is an amphetamine derivative and is a non-neurotoxic potent serotonin-releasing agent and reversible inhibitor of rat monoamine oxidase-A. Analysis of postmortem blood and urine specimens in a case implicating 3,4-methylenedioxymethamphetamine revealed the presence of 4-MTA at a concentration of 4.6 mg/L in femoral blood and 87.2 mg/l in the urine. The concentration of 4-MTA in perimortem blood was measured at 4.2 mg/L. This is the first reported case of death involving 4-MTA in the United Kingdom and the first case known to involve 4-MTA only.     

LC-EI-MS determination of veratridine and cevadine in two fatal cases of Veratrum album poisoning

We report two fatal poisonings due to the ingestion of plant material. The two deceased were discovered in the water of a mountain lake about one month after the postmortem immersion of the corpses. Macroscopic examination of the stomachs revealed the presence of a very large number of small blackish granules, which were later identified as seeds of a Veratrum species. Veratridine and cevadine were identified and quantitated by high-performance liquid chromatography-electrospray ionization-mass spectrometry. Measured blood concentrations were 0.17 and 0.40 ng/mL for veratridine and 0.32 and 0.48 ng/mL for cevadine. The absence of other toxic substance led to the assumption that this massive ingestion was the cause of death, although the circumstances surrounding intake remained unknown.     

Investigations into the stability of 17 psychoactive drugs in a “simulated postmortem blood” model

In the postmortem environment, some drugs and metabolites may degrade due to microbial activity, even forming degradation products that are not produced in humans. Consequently, underestimation or overestimation of perimortem drug concentrations or even false negatives are possible when analyzing postmortem specimens. Therefore, understanding whether medications may be susceptible to microbial degradation is critical in order to ensure that reliable detection and quantitation of drugs and their degradation products is achieved in toxicology screening methods. In this study, a “simulated postmortem blood” model constructed of antemortem human whole blood inoculated with a broad population of human fecal microorganisms was used to investigate the stability of 17 antidepressant and antipsychotic drugs. Microbial communities present in the experiments were determined to be relevant to postmortem blood microorganisms by 16S rRNA sequencing analyses. After 7 days of exposure to the community at 37°C, drug stability was evaluated using liquid chromatography coupled with diode array detection (LC-DAD) and with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Most of the investigated drugs were found to be stable in inoculated samples and noninoculated controls. However, the 1,2-benzisothiazole antipsychotics, ziprasidone and lurasidone, were found to degrade at a rate comparable with the known labile control, risperidone. In longer experiments (7 to 12 months), where specimens were stored at −20°C, 4°C, and ambient temperature, N-dealkylation degradation products were detected for many of the drugs, with greater formation in specimens stored at −20°C than at 4°C.     

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.     

Detection of various performance enhancing substances in specimens collected from race horses in Illinois: a five-year experience

In order to protect the integrity of horse racing in Illinois, a complex testing of urine and blood specimens collected post-race from winning and special designation horses is continuously conducted. The initial screening by immunoassays was followed by the confirmation on presumptive positive samples. Instrumental screening was also conducted. Perimortem and postmortem specimens and special exhibits (syringes, needles, etc.) were also analyzed. The administration of alkalinizing agents was detected by measuring the total plasma carbon dioxide concentration. The laboratory analyzed specimens collected post race from winning horses and special designation horses at eight race tracks in the State of Illinois over the five-year time period (2004-2009). The total number of specimens collected was 91,808, comprising 45,210 urine specimens and 46,598 blood specimens. The total number of violations was 413 (0.45% of the total number of specimens analyzed); 207 were blood specimens (0.44% of the total blood specimens analyzed), and 206 were urine specimens (0.45% of the total urine specimens analyzed). A total of 220 violations were reported for harness horses, and 193 were reported for Thoroughbred horses. The number of reported violations of the total tested specimens in Illinois was small, but a wide variety of performance-enhancing drugs was shown.     

Distribution of methylenedioxymethamphetamine (MDMA) and methylenedioxyamphetamine (MDA) in postmortem and antemortem specimens

With increasing requests for the analysis of various specimens related to fatal and non-fatal abuse of methylenedioxymethamphetamine (ecstasy, MDMA), the toxicology laboratory of the Institute of Forensic Medicine has established protocols for the analysis of MDMA and related compounds in hair, urine, and various postmortem specimens. Analytical protocols include extraction, derivatization, and gas chromatographic-mass spectrometric analysis adapting deuterated analogs of the analytes as internal standards. Data resulting from these analyses and hereby reported include postmortem distribution of MDMA and methylenedioxyamphetamine (MDA) in heart blood, gastric content, urine, and bile specimens from 20 fatal cases; other drugs found in the heart blood from these 20 cases; and the distribution of MDMA and MDA in 25 antemortem urine and 6 hair specimens. The MDA/MDMA concentration ratio observed in a limited number of hair specimens (n=6) are consistent and appear to be higher than those found in other specimens. Compared to other commonly abused drugs (e.g., cocaine and heroin), the "drug/metabolite" concentration ratio (MDMA/MDA) in hair is not significantly different from the ratios derived from other specimens, such as urine and blood. This observation is consistent with the relative drug/metabolite incorporation rates reported for cocaine/benzoylecgonine, tetrahydrocannabinol/tetrahydrocannabinoic acid, and MDMA/MDA.     

Cannabinoids in postmortem toxicology

Cannabinoids are often excluded from postmortem toxicology screens due to their ubiquitous nature, interpretative difficulties and unanswered questions regarding their postmortem redistribution. In this study, we review 30 postmortem cases where a drug screen gave a positive cannabinoids result and a confirmation identified Δ?-tetrahydrocannabinol (THC), 11-hydroxy-Δ?-tetrahydrocannabinol (11-OH-THC), and/or 11-nor-9-carboxy-Δ?-tetrahydrocannabinol (THC-COOH) in peripheral (BL-P) or cardiac/central blood (BL-C) and/or urine (UR). Had cannabinoids not been included in these toxicologic evaluations, incomplete or erroneous inferences would have been drawn in a substantial number of cases regarding cause/manner of death. THC was detected in 28 BL-C and in all 30 BL-P. THC and THC-COOH were confirmed present in 2 and 23 UR, respectively. 11-OH-THC was detected in 4 BL-C, 6 BL-P, and 0 UR. The mean THC concentrations in BL-C and BL-P were 8.0 and 15.8 ng/mL, respectively. The mean THC-COOH concentrations in BL-C and BL-P were 55.2 and 60.6 ng/mL, respectively. The mean 11-OH-THC concentrations in BL-C and BL-P were 17.0 and 12.5 ng/mL, respectively. Postmortem interval (PMI) for each case was determined and evaluated in relation to BL-C/BL-P concentration ratios with THC-COOH exhibiting a possible trend. This study is the first of its kind and demonstrates the usefulness of cannabinoid analyses as part of death investigations. Furthermore, it provides distribution data that will improve the ability of toxicologists and pathologists to evaluate cannabinoid concentrations in human postmortem specimens.