On the first day after drinking small amounts of alcohol, the metabolised products of alcohol are present in the urine. These are the substances ethyl glucuronide and ethyl sulfate. If large amounts of alcohol have been consumed, the substances can be detected in the urine for several days afterwards.
Control of alcohol use
Urine tests are increasingly used to investigate whether a person has consumed alcohol or not in the last day or days. This may be necessary for professional drivers and staff on oil rigs. Internationally, there are many large companies that have strict regulations for alcohol use with regular testing of staff. Some companies require that alcohol should not be consumed the day before work. In Norway, these tests are only used to a limited extent.
The tests are also appropriate for pregnant women.
A new study from the Norwegian Institute of Public Health has examined whether the urine tests for ethyl glucuronide and ethyl sulfate can detect non-alcoholic wine and the use of alcoholic mouthwashes. The mouthwash used in the test contains 21.6 per cent alcohol. 12 people were tested with urine, blood and saliva samples.
Positive urine test
The results show that alcoholic wine gave a positive urine test for ethyl sulfate.
“A likely explanation is that non-alcoholic wines, like some alcoholic wines, contain ethyl sulfate. This is absorbed and excreted in urine. In urine samples it is not possible to distinguish between ethyl sulfate from non-alcoholic wine and ethyl sulfate formed in the body after consumption of alcohol. Therefore, false positive test results are possible,” said Gudrun Høiseth, physician and researcher.
Non-alcoholic wines also contain ethyl glucuronide, but this substance is unlikely to be absorbed. In this study, the researchers could not detect glucuronide in the urine.
Non-alcoholic wines also contain very small amounts of alcohol, up to 0.2 per cent, but the experiments show that such small amounts of alcohol are not detected in some of the tests. Mouthwash was also not detected.
“The conclusion is that people who are regularly tested for alcohol use should be careful not to drink non-alcoholic wine. The urine test for ethyl sulfate is so sensitive that it also shows false-positive results for these drinks,” said Høiseth.
Høiseth G, Yttredal B, Karinen R, Gjerde H, Christophersen A. Levels of Ethyl Glucuronide and Ethyl Sulfate in Oral Fluid, Blood, and Urine After Use of Mouthwash and Ingestion of Nonalcoholic Wine. Journal of Analytical Toxicology , 2010, 34, 84-88.