Ethyl Glucuronide (EtG) is a metabolite created by the body following alcohol consumption. Testing for this metabolite, typically via a urine sample, has become increasingly prevalent in the United States following its initial approval and use in Europe especially by agencies concerned with monitoring an individual for any relapse or return to active drinking. Many favor EtG sampling because it is a “direct” test for alcohol consumption in contrast to older, more traditional tests like Gamma Glutamyl Transferase or Carbohydrate-Deficient Transferrin which look for indirect signs of alcohol use such as liver damage. Further, while older tests generally only become positive following heavy alcohol use, EtG can be present in the urine after only a single drink. Moreover, EtG remains in the body and is detectable in urine three to five days after consumption
Unfortunately, EtG testing has several serious short-comings that limit its viability as an stand-alone objective marker of recent alcohol consumption and relapse. In the area of medical testing, a test is characterized by two qualities: sensitivity and specificity. Sensitivity measures the ability of the test to correctly identify those individuals who do have the condition of interest, here relapse, while specificity measures the ability of the test to correctly identify those persons who do not have the condition of interest. EtG testing has a high sensitivity, that is it has a high probability of correctly identifying as positive an individual who has recently relapsed. However, it also has a low specificity, that is it has a high probability of showing as positive a person who has not recently consumed alcoholic beverages. For example, research has shown that use of everyday items such as bug spray, mouth wash, various over-the-counter medicines, and hand sanitizer can produce positive results. Additionally, without further research, testing facilities have been unable to arrive at a consensus on the level of EtG that should be considered positive for a relapse. The high level of false positives seriously undercuts its status as a viable test for relapse and can easily lend itself to abuse by monitoring agencies such as the Texas Medical Board or the Texas Board of Nursing (Formerly known as the Texas Board of Nurse Examiners).
In fact, EtG’s failings have led the US Department of Health and Human Services to advise cautious interpretation of test results and have expressly stated that use of EtG “is not warranted as a stand-alone confirmation of relapse...” Likewise, Dr. Gegory Skipper, a pioneer and continued advocate of EtG testing, has counseled monitoring agencies that a positive test could very well be the result of incidental exposure to alcohol. These failings readily lead to the test’s misuse by Examining Board’s & Board Staff resulting in a plethora of unwarranted and unfair disciplinary action against their respective licensees.
EtG testing can be an excellent tool to help detect a return to active drinking / addiction, but its shortcomings must be adequately considered. Properly utilized, it affords a compliance officer or State licensing agency an opportunity to confront and question someone about their positive test and specifically inquire as to their program of recovery. Oftentimes a relapse is admitted and can be dealt with swiftly and appropriately. However, if relapse is denied and the licensee’s program appears otherwise strong, the EtG test in and of itself may not provide enough ammunition to warrant disciplinary action.