Comparative analysis of hospital and forensic laboratory ethanol concentrations: A 15 month investigation of antemortem specimens

Quantitative serum alcohol concentrations from regional hospitals (from specimens collected at time of hospital admission) were compared to results from whole blood (from specimens collected at the time of hospital admission) concentrations measured at the San Diego County Medical Examiner's Office (SDCMEO). Over a 15 month period (January 2012 to March 2013), the postmortem forensic toxicology laboratory analyzed a total of 2,321 cases. Of these, 280 were hospital cases (antemortem) representing 12% of the overall Medical Examiner toxicology casework. 59 of the 280 hospital cases (or 21%) screened positive for alcohol (ethanol). 39 of these 59 cases were included in the study based on available specimens for quantitative analyses. This investigation indicated that serum hospital ethanol concentrations correlated well (R(2) = 0.942) with ethanol values determined at SDCMEO (generally measured in whole blood). There was an observed negative bias with an average of -14.1%. A paired t-test was applied to the data and it was shown that this observed bias is statistically significant. These differences in ethanol concentrations could result from differences in specimen, analytical techniques, and/or calibration. The potential for specimen contamination is also discussed.

Ethanol Analysis in Postmortem and Human Performance Forensic Toxicology Cases

Ethanol analysis is probably the most common procedure performed in forensic and analytical toxicology laboratories worldwide. Ethanol poisoning is very important in both clinical and forensic investigations. In clinical evaluations, measuring the ethanol concentration is necessary for the timely and appropriate delivery of care to patients who may experience discomfort or life threatening ethanolic overdose or mixed ethanol-drug intoxication. In forensic toxicology investigations, ethanol is routinely measured in both human performance forensic toxicology cases such as drug-facilitated crimes and driving-under-the-influence cases, as well as in postmortem forensic toxicology cases. This review presents information regarding the most commonly analyzed biological specimens used in alcohol analysis including, among others, blood, breath, urine, oral fluid, and vitreous humor. Additionally, it presents the various chemical, biochemical, gas chromatographic, and breath testing techniques commonly employed in ethanol analysis and considers the main advantages and disadvantages of each. Finally, a brief discussion of quality assurance in alcohol analysis is presented.

An overview of alcohol testing and interpretation in the 21st century

Ethanol analysis is the most commonly carried out drug testing in a forensic toxicology laboratory. Determination of blood alcohol concentration (BAC) is needed in a multitude of situations, including in postmortem analysis, driving under the influence (DUI) and drug-facilitated sexual assault (DFSA) cases, workplace drug monitoring, and probation investigations. These analyses are carried out by direct measurement of ethanol concentrations as well as of metabolic by-products, such as ethyl glucuronide (EtG) and ethyl sulfate (EtS). This review article will discuss pharmacokinetics, including absorption, distribution, and elimination of ethanol, methods for the detection of ethanol, the effect of ethanol on human performance, the role of alcohol in injuries and fatalities, and information regarding the interactions that may occur between alcohol and other drugs. Finally, an explanation will be given on how to interpret alcohol levels as well as the extrapolation and calculation of blood alcohol levels at times prior to sample collection.

On the mammalian acetone metabolism: from chemistry to clinical implications

Despite the description of the ways of acetone metabolism, its real role(s) is (are) still unknown in metabolic network. In this article, a trial is made to ascertain a comprehensive overview of acetone research extending discussion from chemistry to clinical implications. Mammals are quite similar regarding their acetone metabolism, even if species differences can also be observed. By reviewing experimental data, it seems that plasma concentration of acetone in different species is in the order of 10 microm range and the concentration-dependent acetone metabolism is common to all mammals. At low concentrations of plasma acetone, the C3 pathways are operative, while at higher concentrations, the metabolism through acetate becomes dominant. Glucose formation from acetone may also contribute to the maintenance of a constant blood glucose level, but it seems to be only a minor source for that. From energetical point of view, an interorgan cooperation is suggested because transportable C3 fragments produced in the liver can serve as alternative sources of energy for the peripheral tissues in the short of circulating glucose. The degradation of acetoacetate to acetone contributes to the maintenance of pH buffering capacity, as well. Special attention is paid to the discussion of acetone production in diseases amongst which endogenous and exogenous acetonemiae have been defined. Acetonemiae of endogenous origin are due to the increased rate of acetone production followed by an increase of degrading capacity as cytochrome p450IIE1 (CYPIIE1) isozymes become induced. Exogenous acetonemiae usually resulted from intoxications caused by either acetone itself or other exogenous compounds (ethanol, isopropyl alcohol). It is highlighted that, on the one hand, isopropanol is also a normal constituent of metabolism and, on the other hand, the flat opinion that the elevation of its plasma level is a sign of alcoholism cannot further be held. The possible future directions of research upon acetone are depicted by emphasizing the need for the clear-cut identification of mammalian acetoacetate decarboxylase, and the investigation of race differences and genetic background of acetone metabolism.

Measurement of serum isopropanol and the acetone metabolite by proton nuclear magnetic resonance: application to pharmacokinetic evaluation in a simulated overdose model

The purpose of this investigation was to 1) compare the performance of proton nuclear magnetic resonance spectroscopy to gas chromatography head-space analysis in the measurement of serum isopropanol and its metabolite, acetone, obtained during a simulated overdose, and 2) compare pharmacokinetic parameters obtained using the two analytical techniques. Three healthy volunteers ingested 0.6 mL/kg of 70% isopropanol and blood samples were obtained at baseline, 0.16, 0.33, 0.66, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0, 12.0, and 24.0 hours post-ingestion. Resulting sera were analyzed by gas chromatography head-space analysis and proton nuclear magnetic resonance spectroscopy for determination of isopropanol and acetone concentrations. A correlation between concentrations quantitated by gas chromatography head-space analysis versus proton nuclear magnetic resonance spectroscopy was determined using linear regression. Pharmacokinetic disposition parameters were determined from serum concentration-time data and compared using analysis of variance. For isopropanol, the linear regression equation which describes the relationship between gas chromatography head-space analysis and proton nuclear magnetic resonance spectroscopy was y = 1.041x - 2.180 (r2 = 0.995, p < 0.0001); for acetone, y = 1.022x - 0.946 (r2 = 0.984, p < 0.0001). Pharmacokinetic disposition parameters derived from the two analytical methods were comparable. Proton nuclear magnetic resonance spectroscopy can be used to rapidly quantitate serum isopropanol and acetone concentrations in the same sample when gas chromatography head-space analysis is unavailable. Also, proton nuclear magnetic resonance spectroscopy can be used to follow serial serum concentrations during an ingestion for the purpose of pharmacokinetic analysis.

Chromatographic methods for blood alcohol determination

This review is focused on the different chromatographic strategies for blood alcohol determination which can be adopted for clinical and/or forensic purposes. Particular attention is paid to gas chromatography and to high-performance liquid chromatography. However, other analytical techniques in common use, such as chemical and enzymic methods, are also briefly presented, together with some, at present unusual or experimental, approaches, such as enzymic reactors and catalytic electrodes, which are suitable for application in column liquid chromatography. Finally, mention is made of the methods for the determination of acetaldehyde, the major ethanol metabolite, and of some proposed markers of chronic alcohol abuse, such as acetaldehyde-protein adducts and carbohydrate-deficient transferrin. In order to give the background of knowledge for the rational choice of an analytical strategy, an updated outline of ethanol metabolism and toxicology is presented, together with basic information for the interpretation of the results. Problems concerning blood sampling and storage are also discussed.

Serum determinations in toxic isopropanol ingestion

A toxic dose of isopropyl alcohol was ingested by six male mongrel dogs to evaluate the relationship between acetone production and isopropyl degradation. Maximal serum isopropyl levels were achieved approximately 2 to 3 hours after ingestion of 60 mL of 70% isopropyl alcohol. Acetonemia occurred rapidly in the serum (within 15 minutes of ingestion) and continued to rise after isopropanol levels plateaued. The levels of acetone and isopropanol correlated positively throughout the study model with an r of .54 (P less than .001). It is concluded that there is a positive relationship between acetone production and isopropyl metabolism in the setting of a toxic ingestion of isopropanol. Acetone's persistence as a serum marker may be beneficial in identifying isopropyl hours after a suspected ingestion.

Determination of ethanol in human fluids — I. Determination of ethanol in blood

A review of the methods for determination of ethanol in human fluids is presented. This first part of the review deals with the methods for determination of alcohol in blood, which have been divided into chemical, enzymatic, chromatographic and miscellaneous for clearer exposition and discussion.

Blood alcohol analysis: a comparison of the gas-chromatographic assay with an enzymatic assay

Ethanol in blood was assayed by 2 currently available procedures: a commercial kit enzymatic assay and a gas chromatographic procedure. Both methods were performed with commercially available materials and equipment. Results by the 2 procedures agreed well. For the 192 specimens studied, the correlation coefficient was 0.983, and the least-squares values of slope and intercept were 0.999 and 0.001 g/100 ml respectively. Use of isopropanol or ethanol swabs did not affect results of the enzymatic procedure.

Acute isopropyl alcohol intoxication. Diagnosis and management

Alcohol intoxication (methyl, ethyl, isopropyl, and ethylene glycol) is treated frequently in emergency room and intensive care units. Although high morbidity and mortality rates exist, effective therapies for methyl alcohol and ethylene glycol (ethyl alcohol blocking and hemodialysis) and ethyl and isopropyl alcohol (hemodialysis) are available. Prompt and accurate clinical and laboratory differentiation is needed to optimize these therapies. This review presents clinical, pharmacologic, and management data, contrasts important aspects in differential diagnosis, and suggests an appropriate approach to management of isopropyl alcohol intoxication.

Screening for alcohol intoxication by the osmolar gap

Significant ethanol intoxication can be detected by measuring a large osmolar gap, i.e. a large difference between the measured and calculated plasma osmolality. In our laboratory, measurement of the osmolar gap with the application of a correction factor has been used as a screening test for alcohol intoxication and has been shown to be rapid and effective and to compare favourably with an accepted method for assaying ethanol (alcohol dehydrogenase). In only a few clinical situations is a more specific and accurate assay for ethanol required. In interpreting the result, it must be stressed that substances other than ethanol may occasionally cause a raised osmolar gap.