Number of Drinks? Not really. While higher amounts of EtG might indicate larger amounts of alcohol consumption, the exact number is influenced by several factors: the amount and when it was consumed.
The longer the time since consumption, the lower the EtG level see above. Finally, there is a maximum amount of EtG that can be measured, so drinking above that limit might not raise EtG more than can be detected ceiling effect. In some of these tests patients' actual drinking patterns are completely unknown, while in others, positive EtG results led to questioning of the patient who then admitted to alcohol consumption. Other studies deal with people who have consumed substantial amounts of alcohol, such as hospitalized alcohol withdrawal patients, but how much they drank and when they drank is unknown Wurst et al.
The effects of water-induced diuresis i. Studies show that the intake of water prior to urine sampling results in a dramatic reduction in the EtG concentration, while expressing EtG as a ratio to creatinine is not affected by dilution. On the whole, our literature review does convince us that EtG testing is very specific for alcohol. However, it actually revealed very little quantitative information about EtG's sensitivity over time and relative to the amount of alcohol consumed.
Most of the research is designed to find the true positives , but it is not reliable for determining the rate of false negatives. In screening for alcohol abstinence, knowing the rate of false negatives is very important.
In fact, only one published study comes close to answering the question about EtG sensitivity over time and relative to the amount of alcohol consumed Borucki et al.
In this study, 17 test subjects were dosed to severely high levels in a hospital setting. For each test subject, the levels of four biomarkers including EtG were tested eight times over a h period after drinking. In the first 24 h after drinking, all EtG tests were positive. After Based on the fact that limited information was available regarding false negatives, and the fact that all research to-date was conducted in a hospital or lab setting, we decided to conduct our own small study in an office environment using commercially available test kits, just as a monitoring agency would do.
Test participants were recruited by word of mouth and consisted of company employees, friends, and family members. All test subjects were volunteers and fully consented to the work being done in the study and were not paid for their efforts. Each participant self-certified that they were in good general medical health, were a social drinker not dependent on alcohol and were not pregnant females.
All test participants were 21 years of age or older. The alcohol monitoring systems AMS ethics committee did approve this study. Test participant characteristics are summarized in Table 1. Each participant was assigned a target alcohol dose and target waiting period based on random selection of a number from a cup no replacement. We used three different target alcohol doses low, medium, and high and three different target waiting periods 24, 48, and 72 h. Low, medium, and high target doses were defined as 0.
This corresponds to 1. The waiting period was defined as the period of time between completing alcohol consumption and providing a urine sample.
All test participants agreed to completely abstain from drinking alcohol for 5 days prior to the test, and self-reported that they indeed did so. Tests were conducted over a week period, averaging 1. On their scheduled day and time, each test participant selected an alcoholic beverage from among beer, wine, or proof spirits. The volume of drink to be consumed was calculated based on the participant's body weight, the alcohol content of the selected beverage, and the target dose of ethanol.
Drinks were generally rounded up to the nearest We did not require that alcohol be consumed in a specific duration, but we did want to ensure that blood alcohol concentration BAC levels did not achieve dangerously high levels. Therefore, for the medium and high dose groups, a minimum drinking time was suggested to ensure drinking was stretched out over a suitable period. Overall, actual consumption durations ranged from less than 15 min to over 2 h.
However, because BAC does provide a reference point for many readers, we did calculate theoretical BACs for each drinking event using the Widmark formula Anderson et al. After consuming alcohol, each test participant again agreed to completely abstain from alcohol throughout their waiting period until after they provided a urine sample. A summary of actual alcohol doses and waiting periods for test participant is shown in Table 2.
Due to the voluntary nature of testing, we did not directly observe the test participants when providing the sample, but we made every other effort to use the same protocol that a typical monitoring agency would use. On several occasions the sample was collected after the courier's PM pick-up time.
Test participants were referred to by a 4-digit ID number on all paperwork to ensure their privacy. To reduce the opportunity for false positives, the lab uses the same two-step process for EtG testing that is used for most urine tests. That is, the first test is referred to as a screening test.
If the screening test is positive, then a second test is performed as a confirmation test. The second test must also be positive in order to confirm the specimen is positive for EtG.
It should also be noted that urinary creatinine levels were not monitored. To ensure our specimens were treated the same as those delivered from any monitoring agency, NWT was not aware of the fact that we were performing a scientific study. Those situations are better suited for a breathalyzer test. The EtG test can only confirm that a person has not consumed alcohol or alcohol containing products in the days leading up to the test. Unfortunately, there are many items that contain alcohol people can encounter on a daily basis, such as:.
The Household Products Database, published through the National Library of Medicine, allows individuals to search for products that contain alcohol. All of those products have the potential to affect the results of an EtG test.
A negative EtG test shows that a person was not exposed to ethanol within the testing time frame up to five days. A positive EtG test usually confirms a person was exposed to ethanol within the days leading up to the urinalysis. These amounts of EtG could be due to heavy drinking within three days of the test, light drinking in the past 24 hours, or intense exposure to products containing alcohol recently.
However, it could also mean that the person was exposed to alcohol-containing products as well. In addition to ethanol exposure, there are some situations and circumstances in which a person may have a positive EtG test without consuming an ethanol product. If a urine sample is not stored properly and remains too long at room temperature, EtG levels rise due to bacteria growth in the urine.
Refrigeration of samples is suggested for any EtG test that cannot be shipped within the recommended time frame. A person with diabetes who has a urinary tract infection may produce EtG and result in a positive test.
This can only occur in individuals who have diabetes. Failing a drug or alcohol screen can be an indication that a person is struggling with a substance abuse problem, especially if the testing is expected.
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