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Accuracy of an Enzymatic Assay Device for Sermn Ethanol Measurement

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Abstract

To determine the accuracy of an enzymatic assay of serum to measure blood ethanol levels in the emergency department. A blinded, prospective study of emergency department patients for whom a blood ethanol was ordered and performed. After skin prep with betadine, two blood samples were drawn into separate sodium fluoride-containing vacutainers. One sample was sent to the hospital laboratory for blood ethanol analysis. The other was centrifuged for 5 minutes and the serum was then assayed using the QED A350 Saliva Alcohol Test. Values were then compared by kappa statistic and Pearson's correlation. Sensitivity and specificity calculations were determined for the QED device to detect a blood ethanol > 100 mg/dL. Sixty-six patients were enrolled. The kappa value for QED compared to lab blood ethanol was 0.93. The Pearson's correlation coefficient was 0.94. The QED, in general, tended to overestimate blood ethanol slightly. The QED was 100% sensitive and 82% specific in detecting a blood ethanol > 100 mg/dL. Analysis of serum using a QED A350' is a sensitive and accurate index of low to moderate increases in blood ethanol appropriate to emergency department, but not legal, interpretation.
... 22 On the basis of blood ethanol levels of greater than 100 mg/dL, QED A350 exhibited 100% sensitivity and 82% specificity. 23 AbuSign DOA 4 (Princeton Bio-Meditech Corporation, Princeton, NJ), an immunochromatographic test, 24 was used to examine urine for the presence of cocaine, marijuana, amphetamines, methamphetamine, benzodiazepines, barbiturates, phencyclidine, and opioids or their metabolites. With gas chromatography-mass spectrometry serving as the criterion standard and validation limited to cannabinoids, AbuSign test slides (at a cut-off point of 50 ng/mL) registered 87% sensitivity and 51% specificity. ...
... False-negative results likely outweighed false-positive results in both screening tests. 23,25 Moreover, the rapid metabolization of ethanol means that saliva testing would have underestimated the association of alcohol with ED cases. The urinalysis was constrained by the limited types of drugs that could be tested and because the time window for assessing recent use varies widely with drug type and dose. ...
Article
Health care providers in hospital emergency departments rarely take substance abuse histories or assess associated treatment need. This study compares documentation of psychoactive drug-related diagnoses for adult ED patients in medical records with treatment need assessed through self-report, toxicologic screening, and Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), criteria. A statewide, 2-stage, probability sample survey was conducted in 7 Tennessee general hospital EDs from June 1996 to January 1997. Main outcome measures were the prevalence of diagnosed substance abuse problems, positive bioassay results, denied use, and treatment need. Sensitivity and multivariate analyses were conducted by using varied case definitions of treatment need. Thirty-one percent (95% confidence interval [CI] 27.3% to 34.7%) of screened ED patients (n=1,330) had positive test results for substance use. Their prevalence of denial of use in the 30 days before the survey ranged from 10% for alcohol (95% CI 5.7% to 14.3%) to 100% for phencyclidine. One percent of all ED patients (n=1,502) had a recorded diagnosis of substance abuse. By contrast, as many as 27% (95% CI 23.3% to 31.8%) were assessed as needing substance abuse treatment on the basis of a comprehensive case definition that accounted for denial and positive test results. A sensitivity analysis using other case definitions is also presented. For example, 4% (95% CI 2.8% to 5.3%) of patients met the very strict definition of DSM-IV current drug dependence only. Under the comprehensive case definition, TennCare patients (adjusted odds ratio [OR] 1.63; 95% CI 1.30 to 2.05) and Medicare patients (adjusted OR 2.50; 95% CI 1.34 to 4.65) showed excess treatment need relative to the privately insured. Excess need was also exhibited by patients reporting 1 or more prior ED visits in the past year (adjusted OR 1.62; 95% CI 1.13 to 2.31) and by patients taking 2 or more hours to reach the ED after the onset of injury or illness (adjusted OR 1.54; 95% CI 1.16 to 2.04). Treatment need was inversely associated with age. Irrespective of case definition, less than 10% of ED patients who needed substance abuse treatment were receiving such treatment. EDs can be important venues for detecting persons in need of substance abuse treatment.
... Although the device is approved by the Food and Drug Administration only for use with saliva, a study has shown it can be used with heparinized or fluorinated plasma. 20 None of the devices used to determine the presence of ethanol in saliva provide definitive test results. Although they are reliable for screening, confirmation of positive test results should be performed using whole blood with GC in potential medicolegal cases. ...
Article
Testing for ethanol abuse is performed by clinical laboratories and by emergency medicine and law enforcement personnel. Although the definitive approach to determine ethanol intoxication for clinical or medicolegal purposes is whole blood analysis by gas chromatography, most laboratories and other testing facilities do not have such capabilities. In the clinical laboratory, ethanol is measured routinely in serum or plasma by using high- volume or benchtop analyzers. However, point-of-care testing devices can be used to screen other biologic fluids and breath. Many alternative devices have been approved by the US Department of Transportation and, thus, have become popular for workplace testing in the private sector. Breath-alcohol analysis is the most popular means for determining impairment in a medicolegal setting by law enforcement agencies.
Article
Full-text available
A static headspace gas chromatography coupled mass spectrometry (GC-MS) method was developed and fully validated for the quantitative measurement of acetaldehyde, acetone, methanol, ethanol and acetic acid in the headspace of micro-volumes of blood using n-propanol as an internal standard. The linearity of the method was established over the range 0.2–100 mg/L (R 2 > 0.99) and the limits of detection were 0.1–0.2 mg/L and lower limits quantification 0.5–1 mg/L. Precision and accuracies fell within acceptable limits (20 % for LLOQ and 15 %) for both intra- and inter-day analyses for all compounds except acetaldehyde which had inter-day variability of ≤25 %. The method was applied to analyse blood samples from neonatal patients receiving courses of ethanol excipient containing medications. Baseline levels of acetaldehyde, acetone, methanol and ethanol could be measured in patients before dosing commenced and an increase in levels of some volatiles were observed in several neonates after receiving ethanol-containing medications.
Chapter
This chapter provides an overview of the methods of determining Blood Alcohol Concentration (BAC) that are useful in alcohol research. BAC refers to the amount of alcohol circulating in the bloodstream, and is the best estimate of the effects of alcohol on the brain. BAC varies as a function of dose of alcohol, time, gender, body weight, age, beverage type, and individual differences in absorption and metabolism of alcohol. BAC measurement allows for a direct comparison of intoxication levels across persons. Although direct blood alcohol measurement via gas chromatographic methods remains the standard, BAC can be estimated from other bodily fluids, including saliva, urine, and sweat, and from the breath samples. In addition, predictions can be made using mathematical models of BAC that take into account major factors affecting the absorption and metabolism of alcohol. Both advantages and disadvantages of each method of BAC determination are reviewed. Limitations relate both to the biological correspondence of the sample tested to the actual BAC and to the current instrumentation available for analysis. When choosing among BAC measurement options, the resources available, the level of accuracy required, and the nature of the inferences to be made, must be considered.
Article
Numerous bedside diagnostic modalities are appropriate for the practice of emergency medicine. The proliferation of sophisticated technology is likely to increase both the availability and accuracy of commercial testing products. If health care reform in the United States results in a relaxation of the CLIA regulations, there will be a rapid expansion of research and development aimed at the biotechnology market. How much this would pertain to hospital-based emergency practice remains to be seen. Cost containment pressures may act in both directions on the utilization of available bedside technology. Although these tests are often less expensive than centralized laboratory determinations, the ready availability of near-patient testing may result in an increase in use that negates the lower cost. As with other diagnostic modalities, a thoughtful, considered approach based on scientific evidence will be necessary to formulate the appropriate use of bedside testing in individual emergency practice settings.
Article
We have investigated the applicability of the Q.E.D. (Quantitative Ethanol Detector) and Aloco-Screen test kits for screening ethanol concentrations in forensic samples, such as hemolyzed/decomposed blood, urine and vitreous humor. Because both kits were based on enzymatic color reactions, direct application of the kits to hemoglobin-rich samples gave unsatisfactory results. The deproteinization of blood with trichloroacetic acid followed by membrane filtration overcame such problem. This procedure was also effective for pretreatment of urine and vitreous humor samples to suppress excessive color development in the Alco-Screen test. The ethanol concentrations in whole blood (n = 29), urine (n = 7) and vitreous humor (n = 6) samples determined by the Q.E.D. kit correlated well with those determined by gas chromatography; the correlation coefficients were 0.986, 0.975 and 0.993, respectively. Because of its high specificity and sensitivity to ethanol, Q.E.D. seems to be highly reliable for quantitative estimation of ethanol concentrations in forensic samples. Alco-Screen also had high sensitivity, the specificity to ethanol was relatively low; the color reaction was also observed in the presence of acetone, n-propanol, toluene, methanol, ethylene glycol, methamphetamine, diazepam and dichrovos. Therefore, if forensic samples are analyzed by the Alco-Screen, it is essential to confirm the positive results using other analytical methods.
Article
The widespread nature of alcohol-related motor vehicle collisions suggests inadequacies in the system for deterring alcohol use when driving. This study was performed to determine whether hospitalization is a component in a "system failure" that allows injured, alcohol-impaired drivers to escape arrest and conviction for driving under the influence (DUI). We conducted a retrospective review of medical and court records of intoxicated drivers injured in a motor vehicle collision who were transported to our Level I trauma center from January 1, 1997, through December 31, 1998. Of the 213 intoxicated drivers in our study, 172 (81%) were followed up by law enforcement officials, and 156 (73.2%) were arrested for DUI. Of those who were arrested and completed court hearings, 135 (93.8%) were convicted for DUI. These values are higher than those reported in previous studies and indicate that hospitalization does not "protect" injured, intoxicated drivers in our community.
Article
The disposable QED saliva alcohol test provides a very simple, fast, and reliable means for quantitative onsite alcohol detection. The purpose of this study was to determine if the QED test would be a useful tool for the determination of postmortem ethanol levels in cases where a rapid result was needed. QED results were compared with ethanol levels determined by headspace GC analysis. Both saliva and vitreous humor specimens were used for the evaluation. QED tests were initially attempted using the oral fluid from 50 individuals. Of these cases, 17 of the tests were valid with 8 positive results. For 23 cases the oral fluid was not attainable, and for 10 cases, the sample was contaminated with blood making the tests invalid. The correlation between the oral fluid results and the blood headspace GC analysis was poor (r = 0.8345) over the range of 0.01-0.29 g/dL. Vitreous specimens were found to be the matrix of choice for analyzing postmortem cases using the QED. Only 6 of 171 specimens were found to be unsuitable. The QED results correlated well with the headspace GC analysis (r = 0.9931, n = 165). When using ethanol levels > 0.02 g/dL (n = 126), an average vitreous (GC)/blood ratio of 1.16 correlated well with the average QED/blood ratio of 1.22. Although the QED saliva alcohol test does not appear to be useful in determining postmortem saliva ethanol levels, it does provide accurate results when using postmortem vitreous humor as the testing matrix.
Article
In this paper, the applicability of the quantitative ethanol detector (QED) test kit for screening of ethanol concentrations in blood samples was investigated. The pretreatment of blood using the sulfosalicylic acid solution and the three-way stopcock followed by membrane filtration gave satisfactory results. The ethanol concentrations in whole blood samples (n=61) determined by QED correlated well with those determined by gas chromatography; the correlation coefficient indicated 0.990. Because a high correlation coefficient (0.928) was also confirmed in trial by investigators, QED test should be highly considered for ethanol screening in forensic praxis.
Article
There is a continuing increase in the use of immunological techniques in the field of clinical toxicology. This is primarily due to the rapidity by which analytical results are now required, and can be obtained, following the testing of individuals for drug use. There has recently been an increase in the repertoire of assays now available to testing laboratories (e.g., buprenorphine and heroin metabolite assays), with the techniques themselves becoming increasingly more specific for the drugs and/or metabolites being monitored (e.g., methadone metabolite assays). The near patient testing (NPT), or point-of-care testing (POCT), devices are now several generations forward from their inception, with some tests now approaching the sensitivity and specificity of automated laboratory-based methods. This review has been collated from the literature to illustrate some of the possible reasons for the move towards the increasing use of immunological techniques, and to highlight some of the advantages and disadvantages associated with such drug screening methods. In particular, it has been shown that it is important to determine, monitor and review the knowledge and training of the individual using the technique. In addition, quality control and quality assessment are paramount to ensure the validity of any drug testing being performed. It has also been shown that it is vital to maintain and develop the relationships between the staff performing the testing, the laboratory (if the testing is performed using NPT devices), and the clinicians utilising the results obtained from drug testing. Without these links, interpretive errors could arise which could adversely affect the diagnosis and management of patients.
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Scientific investigations have produced 50 years of accumulated evidence showing a direct relationship between increasing blood alcohol concentration (BAC) in drivers and increasing risk of a motor vehicle crash. There is scientific consensus that alcohol causes deterioration of driving skills beginning at 0.05% BAC or even lower, and progressively serious impairment at higher BACs. Drivers aged 16 to 24 years have the highest representation of all age groups in alcohol-related road crashes; young drivers involved in alcohol-related fatal crashes have lower average BACs than older drivers. Alcohol impairs driving skills by its effects on the central nervous system, acting like a general anesthetic. It renders slower and less efficient both information acquisition and information processing, making divided-attention tasks such as steering and braking more difficult to carry out without error. The influence of alcohol on emotions and attitudes may be a crash risk factor related to driving style in addition to driving skill. Biologic variability among humans produces substantial differences in alcohol influence and alcohol tolerance, making virtually useless any attempts to fix a “safe ” drinking level for drivers. The American Medical Association supports a policy recommending (1) public education urging drivers not to drink, (2) adoption by all states of 0.05% BAC as per se evidence of alcohol-impaired driving, (3) 21 years as the legal drinking age in all states, (4) adoption by all states of administrative driver's license suspension in driving-under-the-influence cases, and (5) encouragement for the automobile industry to develop a safety module that thwarts operation of a motor vehicle by an intoxicated person.
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Study objective: To evaluate the accuracy of the Q.E.D.(TM) A-150 Saliva Alcohol Test, a new device that gives a specific quantitative blood alcohol level by measuring saliva alcohol concentration in the range of 0 to 150 mg/dL. Study design: Forty-two healthy volunteers consumed 4.5 to 6 oz of alcohol in the form of beer, wine, or liquor over a 90-minute period. Blood and saliva samples were obtained for alcohol measurement at 30, 60, 90, and 120 minutes after the last drink. Blood samples were analyzed within 24 hours by gas chromatography at a commercial clinical laboratory. Saliva samples were tested immediately using the new Q.E.D.(TM) A-150 Saliva Alcohol Test. Results: Excellent correlation was observed between saliva and blood alcohol levels over the range 0 to 150 mg/dL (slope = 1.0; intercept = 2.4; r = .98). Conclusion:The Q.E.D.(TM) Test is an accurate device for specific quantitative measurement of alcohol levels using saliva.
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Establishes the property that if Vij = (c-j)2 (Vij denotes the disagreement weight in the weighted Kappa formula) and if the variables can be scaled 1 and 2, then irrespective of the marginal distributions, weighted Kappa is identical with the intraclass correlation coefficient in which the mean differences between the raters is included as a component of variability. A discussion of this property is presented along with an example. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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In clinical measurement comparison of a new measurement technique with an established one is often needed to see whether they agree sufficiently for the new to replace the old. Such investigations are often analysed inappropriately, notably by using correlation coefficients. The use of correlation is misleading. An alternative approach, based on graphical techniques and simple calculations, is described, together with the relation between this analysis and the assessment of repeatability.
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The blood:breath alcohol ratio, commonly used to translate the result of breath alcohol analysis into the co-existing blood alcohol concentration, varies from person to person and within one person over time.
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A helium-neon laser was used to measure the alcohol content of breath from six volunteers at regular intervals over up to four hours. The corresponding blood values were calculated with a blood : breath partition coefficient of 2100. When these values were compared with those obtained by direct measurement it was obvious that substantial variations occurred from one person to another in the derived values and that even in the same person the use of the partition coefficient of 2100 led to significant differences between the direct and derived values for blood, and these differences changed with time. Thus the assertion that a constant partition coefficient of 2100 exists between alcohol in blood and that in breath is not supported by the evidence. Accordingly the use of such a partition coefficient to derive blood alcohol values for law enforcement is not justified.
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To evaluate the accuracy of the Q.E.D. A-150 Saliva Alcohol Test, a new device that gives a specific quantitative blood alcohol level by measuring saliva alcohol concentration in the range of 0 to 150 mg/dL. Forty-two healthy volunteers consumed 4.5 to 6 oz of alcohol in the form of beer, wine, or liquor over a 90-minute period. Blood and saliva samples were obtained for alcohol measurement at 30, 60, 90, and 120 minutes after the last drink. Blood samples were analyzed within 24 hours by gas chromatography at a commercial clinical laboratory. Saliva samples were tested immediately using the new Q.E.D. A-150 Saliva Alcohol Test. Excellent correlation was observed between saliva and blood alcohol levels over the range of 0 to 150 mg/dL (slope = 1.0; intercept = 2.4; r = .98). The Q.E.D. Test is an accurate device for specific quantitative measurement of alcohol levels using saliva.
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To determine the reliability of a recently developed electrochemical meter to rapidly (within 60 seconds) measure blood alcohol concentration (BAC) in the emergency department. A prospective study comparing the meter data with that of immunoassay and gas chromatography criterion standards undertaken during a ten-week period. Adult ED of a municipal hospital. Three hundred eighty-three consecutive patients with altered mental status or suspected alcohol intoxication. Each patient underwent routine phlebotomy, and blood samples were obtained for meter and immunoassay BAC determinations. The first 60% of patients also underwent gas chromatography BAC determination. Two hundred nineteen patients (60%) had BAC detectable by both meter and immunoassay. BAC measurement by the meter correlated strongly with immunoassay and gas chromatography determinations (Pearson's correlation coefficient, r = .94; P less than .00000001 for both correlations). The electrochemical meter provides a rapid and reliable BAC measurement in the ED.