BRIEF REPORT

blood alcohol level, testing

Evaluation of the

Q.E.D. Tn Saliva

Alcohol Test:

A New, Rapid, Accurate Device for Measuring Ethanol in Saliva I

From the Division of Emergency Medicine, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania. Received for publication February 25, 1991. Revision rebeived March 11, 1992. Acceptedfor publication April 12, 1992. This clinical trial was funded by Enzymntics, luc, Horsham, Pennsylvania. Presented at the Societyfor Academic Emergency Medicine Annual Meeting inMinneapolis, Minnesota, May 1990.

Theodore A Christopher,MD, FACEP Joseph A Zeccardi, MD, FACEP

Study objective: To evaluate the accuracy of the Q.E.D.T M 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.DP 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.T M Test is an accurate device for specific quantitative measurement of alcohol levels using saliva. [Christopher TA, Zeccardi JA: Evaluation of the Q.E.D.T M Saliva Alcohol Test: A new, rapid, accurate device for measuring ethanol in saliva. Ann EmergMedSeptember1992;21:1135-1137.]

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SALIVA ALCOHOL TEST Christopher & Zeccardi

INTRODUCTION

MATERIALS

The prevalence of recent alcohol consumption for patients visiting hospital emergency departments ranges from 32% to 61%. 1 Medical problems associated with ethanol intoxication include multiple t r a u m a , metabolic disturbances, drug overdose, behavioral emergencies, and coma. 2 It is i m p o r t a n t to distinguish altered mental status due to alcohol intoxication from other causes. Clinical diagnosis of alcohol intoxication at high levels is not necessarily easy. Many victims of head t r a u m a with altered mental status require an alcohol measurement to distinguish head t r a u m a and other intoxications from alcohol intoxication. At levels less than 100 mg/dL, clinical diagnosis is accurate less than 68% of the time. 3 The p r e f e r r e d method for quantitative ethanol analysis is gas chromatography using whole venous blood. However, this method is time-consuming, expensive, and requires skilled l a b o r a t o r y technicians to operate the •equipment. Nasal or oral breath alcohol meters have been demonstrated to be both r a p i d and accurate when used on some subjects. 102 However, the accuracy of b r e a t h alcohol meters may be compromised by b r e a t h specimens contaminated with residual alcohol from recent alcohol consumption, vomitus containing alcohol, and by eructation of gas containing alcohol. 4 In addition, measurements of b r e a t h alcohol may not be accurate in febrile or hypothermic patients, unconscious victims, or patients with b r o n c h o p u l m o n a r y disease, a Saliva testing is accurate in these patients. If specimen collection is delayed ten minutes from the ingestion of alcohol, no interference is observed in the assay. Studies conducted in clinical laboratories have been reported in the literature and support the close correlation between blood and saliva alcohol levels.5, 6 However, no rapid, quantitative, alternate site saliva alcohol test methods have been available. A semiquantitative color change dipstick test has been evaluated in the clinical setting but did not demonstrate acceptable performance. 7 The purpose of this study was to assess the accuracy of a new device that gives specific quantitative blood alcohol levels by measuring saliva alcohol concentrations.

Forty-two healthy volunteer subjects ranging in age from 21 to 60 years participated in the study. The group included approximately equal numbers of men and women. All subjects were asked to abstain from alcohol consumption for 24 hours before the study. Subjects consumed approximately one d r i n k , in the form of beer, wine, or hquor, every 18 minutes for a 90-minute period. Each subject consumed a total of 4.5 to 6 oz of alcohol. Food was available throughout the study, and the subjects were encouraged to eat. Beginning 30 minutes after the last d r i n k of alcohol, blood and saliva specimens were collected. Sample collection was repeated again at 60, 90, and 120 minutes after the last drink. Blood was collected in 7-mL potassium oxalate vacutainer tubes by venipuncture in the commonly accepted manner. Saliva was collected using the sample collection swab supplied with the Q.E.D. product. To minimize metabolic variation, blood and saliva samples were collected within two minutes of each other. Blood was t r a n s p o r t e d to a local clinical l a b o r a t o r y where it was analyzed within 24 hours by gas chromatography. Saliva was tested at once using the Q.E.D. device. To perform the Q.E.D. TM Saliva Alcohol Test, the patient's mouth was swabbed for 30 to 60 seconds to saturate the cotton collective swab, which was then pressed into the device to express saliva into the reaction capillary. The Q.E.D. Saliva Alcohol Test result a p p e a r e d as a color b a r and was r e a d within two minutes, similar to reading a fever thermometer. The simple procedure and straightforward interpretation required minimal training. The device uses a novel modification to the widely used alcohol dehydrogenase method (Figure). Saliva specimens containing more than 10 mg/dL of alcohol cause a controlled color reaction to develop in the Q.E.D. device, producing a blue bar. The test result is r e a d from a scale printed on the device at the point where the blue b a r stops.

Figure. Chemical reaction sequence Alcohol Dehydrogenase Ethanol + NAD* Acetaldehyde + TRIS*

Acetaldehyde + NADHt + H+ Complex

Diaphorase NADH + Electron Sink

NAD + H2-Electron Sink

Diaphorase NADH + Tetrazolium Salt

NAD + Formazan Dye

*Nicotinamideadeninedinucleotide. tReducedform of NAD. *Tris (hydroxymethyl)aminomethane.

SEPTEMBER1992 21:9 ANNALS0F EMERGENCYMEDICINE

AND

METHODS

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RESULTS

Forty-two subjects p a r t i c i p a t e d in the study, yielding a total of 168 blood and saliva specimens. The range of alcohol levels for both blood and saliva samples was 0 to 145 mg/dL. No samples were in excess of 150 mg/dL. Comparison of the methods using linear regression analysis yielded the following equation: Y = 1.0X - 2.4. Excellent correlation was obtained between the saliva and blood samples (r = .98; Sy,x = 7.3). _Allblood alcohol levels less than l0 mg/dL were r e p o r t e d "0" by saliva testing. In no instance did the difference between the two methods exceed 15 mg/dL. DISCUSSION

This study demonstrated that there is a close correlation between blood alcohol levels determined by gas chromatogr a p h y and saliva alcohol levels measured by the Q.E.D. A-150 Saliva Alcohol Test. Clinical applications for such a TM

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p r o d u c t include prehospital and ED assessment of patients with altered mental status8 as well as predischarge testing to be used in conjunction with chnical findings that may not always reveal impairments in judgment and fine motor control common with low-level alcohol intoxication. The decision to o r d e r an alcohol test in an ED setting is not without controversy. In practice, a test should be o r d e r e d if it will benefit the patient's treatment. There is a clear benefit to ordering a blood alcohol test to distinguish altered mental status caused by alcohol intoxication from other causes. However, because of the cost and time involved, the benefit of ordering a l a b o r a t o r y alcohol test for other p u r poses, including determining a patient's readiness for discharge, is less apparent. The Q.E.D. Saliva Alcohol Test provides a logical and effective resolution to some of the controversy surrounding the decision to o r d e r a test. Sample collection is easy, and t h e test result is available in less than two minutes. The device produces a clear, sharp end point and incorporates an internal positive control to assure the user that the test has been performed properly and that the reagents contained within the product are fully functional. The device is disposable and requires no instrumentation. The p r o d u c t is highly specific for ethanol and is not subjected to interference from other alcohols, common medications, or digestive enzymes. Although the Q.E.D. Saliva Alcohol Test offers advantages over existing test methods, some limitations, including those found in handheld b r e a t h alcohol instruments, affect this product. The m a n u f a c t u r e r recommends that this test be performed at least ten minutes after the last consumption of alcohol. Vomitus containing alcohol will also produce a falsely elevated test result if the same ten-minute waiting period is not observed. P r o p e r test performance requires that the sample collection swab be thoroughly saturated with saliva. In this study, there was little difficulty obtaining sufficient sample to p e r f o r m the test; however, in patients with " d r y mouth," collecting sufficient saliva may be difficult. The importance of a fast, accurate, inexpensive predischarge alcohol test becomes more evident when considering current methods for determining readiness for discharge. These include chnical assessment of mental status as well as calculation of approximate blood alcohol levels based on average rate of elimination. Ehmination rates may vary from 12 to 15 mg/dL per hour for nondrinkers to 30 to 50 mg/dL p e r hour for alcoholics. 9 As Simel and Feussner 1° suggested, discharge "driving prescriptions"(ie, advising an intoxicated patient when she or he may drive without impairment) would be more accurate if alcohol levels were determined initially or on discharge. Other potential clinical applications include screening patients in alcoholic rehabilitation programs and preemployment, occupational, and industrial health settings. The device may also be useful in screening individuals in safety-sensitive positions and in athletic events and school systems. Finally, it may be useful forensically in the screenTM

TM

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ing of intoxicated automobile drivers. It is not unusual for patients admitted to the ED to have blood alcohol levels in excess of 150 mg/dL; levels of 220 to 300 mg/dL are not uncommon. The Q.E.D. A-150 Saliva Alcohol Test result on these patients is r e p o r t e d as "greater than 150 mg/dL." A p r o d u c t with a dynamic range of 0 to 350 mg/dL may be more useful in ED applications. TM

CONCLUSION The Q.E.D. A-150 Saliva Alcohol Test is an accurate device for specific quantitative measurement of saliva alcohol levels. TM

REFERENCES 1.6erberich $6,6erberich BK, Fife D, et al: Analysis of the relationship between blood alcehol and nasal breath alcohol concentrations: Implications for assessment of trauma cases. J Trauma 1989;29:338-343. 2. Gibb KA, Yee AS, Martin SD, et al: Accuracy and usefulness for a breath alcohol analyzer. Ann Emerg Med 1984;13:516-520. 3. AMA Council on Scientific Affairs: Alcohol and the driver. JAMA 1986;256:1461-1466. 4. 6ibb K: Screen alcohol levels, toxicology screen, and use of the breath alcohol analyzer. Ann Emerg Med1988;15:349-35& 5. Jones AW: Inter and [ntra individual variation on the saliva/blood alcohol rates during ethanol metabolism in man. Clin Chem1979;25:1394-1398. 6. Jones AW: Distribution of ethanol between saliva and blood in man. Clin Exp Pharmacol Physio11979;6:53-59. 7. Schwartz RH, O'Donnell RM, Thorne MM, et al: Evaluation of colormetric dipstick test to detect alcohol in saliva: A pilot study. Ann Emerg Med 1989;18:1001-1003. 8. Harpe K6, Yealy DM, Hailer MB, et al: Saliva alcohol reagent strips in altered response protocols. Prehosp Ois Med 5:41-44, 1990. 9. Winek CL, Murphy KL: The rate and kinetic order of ethanol elimination. Forensic Sci Int 1984;25:159-166. 10. Simel DL, Feussner JR: Blood alcohol measurements in the emergency department: Who needs them? Am J Pubfic Health 1988;78:1478-1479. Address for reprints: Theodore A Christopher, MD, FACEP Division of Emergency Medicine Thomas Jefferson University Hospital, Room 293 ThomPson Building 111 South 1lth Street Philadelphia, Pennsylvania 19107

ANNALS OF EMERGENCY MEDICINE

21:9

SEPTEMBER1992

Evaluation of the Q.E.D. Saliva Alcohol Test: a new, rapid, accurate device for measuring ethanol in saliva.

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 sal...
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