New: Ethanol-based handsanitizing gel vapor causes positive alcohol marker, EtG, - unpublished but available for viewing <here>.
New Alcohol Markers - Proper use and interpretation
History
Ethylglucuronide (EtG) was described as early as the 1950's, however, clinical use of the test as an alcohol marker began in 2001 when Dr. Friedrich Wurst, in Switzerland, and Dr. Gregory Skipper, reported a study of alcoholics in a psychiatric facility in Germany. Their findings demonstrated that EtG was a more sensitive and reliable indicator of both drinking and abstinence than was urine alcohol. Dr. Skipper, who oversees a monitoring program for physicians, had been looking for a more reliable means of reliably documenting alcohol abstinence. He desired to study the test further for use in physicians in monitoring who'd committed to abstinence in order to return to work. It rapidly became clear that urine EtG would be a valuable test in monitoring professionals. The Federation of State Physician Health Programs estimates that over 9,000 physicians are in monitoring in the USA. An essential issue in justifying the continued safe practice of recovering physicians involves being able to reliably document abstinence.
In order for EtG testing to be practical in the United States it was important to convince a lab in this country to implement testing. Dr. Skipper went to Pennsylvania and met with the owner and chief toxicologist at National Medical Services and "made the case for EtG testing." He was able to convince NMS to begin performing the test. Through coordination with Wolfgang Weinmann's lab in Germany, the only lab then performing EtG testing, the necessary "deuterized standards" from Germany were obtained and NMS began performing EtG testing at the cost of $75 per test in 2003.
Once EtG testing was available in the USA additional studies were conducted that reported the effectiveness of the test in monitoring health professionals (example). Use of EtG testing spread very rapidly among physician health programs and soon among others.
Several important issues then began to emerge that frame the complexities of interpreting these tests. It's important to understand their limitations, as with all tests, and to use them properly. Some of these issues are discussed in more depth elsewhere on this site and include:
- Incidental Exposure: Claims of "false positive EtG tests" from incidental exposure to alcohol began to occur. Dr. Skipper developed a an online registry and listserve for for those who claimed they'd been falsely accussed of drinking. The clamor of concern among this group rose rapidly and became extremely vigorous. Several persistent participants convinced Dr. Skipper that this problem was real. This phenomenon of incidental exposure is very similar to the phenomenon of poppy seeds causing positive tests for morphine and is discussed in more depth in a separate section of this website.
- Topical Alcohol as a Source of Incidental Exposure: Based on a particular participants insistence that she had not consumed alcohol but likely had a positive test from alcohol-based handgel, she and Dr. Skipper decided to test the hypothesis. To do this she was admitted to a treatment center in California where pre and post handgel use EtG tests were performed. This trial demonstrated that alcohol-based handsanitizing gel caused positive EtG tests, suggesting an additional source of incidental exposure. This was later corroborated in the lab using 24 volunteers. The surprise finding, in this later study, was that alcohol absorbed through inhalation of vapor, rather than through skin, was the chief source of exposure. (see unpublished study)
- Stability and Synthesis of EtG: It was known that EtG could occasionally disappear (or be degraded) in urine stored at room temperature but not if frozen or heated. Researchers in Scandinavia further clarified this phenomenon when they reported that EtG (but not EtS) could be degraded in urine due to certain bacteria (explaining why heating or cooling samples resulted in less degradation). Furthermore, they then reported that in the presence of alcohol (fermented or added to urine) EtG could be synthesized by similar bacteria in-vitro. This finding supported the likelihood that ethylsulfate (EtS), another minor metabolite of alcohol, is a superior marker, in that it is more sensitive and specific.
- Reliability: Despite the possibility of incidental exposure, (there are many sources of incidental exposure in our environment) most people who test positive for EtG actually did drink in the few days preceding the test. Approximately 50% of individuals, in the author's hands, admit drinking when supportively confronted. Subsequently, another 40% come to admit drinking over time. Those who initially deny drinking should receive more careful monitoring, testing, or other treatment, however, without other proof, they should not be presumed to have been drinking (Dr. Skipper issued an advisory to this effect in 2004 but it went largely unheeded, therefore, he went to Washington DC and met with the director of the Center for Substance Abuse Treatment and implored SAMHSA to issue an advisory. Dr. Skipper, along with other alcohol marker experts from the National Institute of Alcoholism and Alcohol Abuse, wrote the SAMHSA advisory warning against over reliance on a positive EtG as sole proof of drinking.)