What about urine alcohol produced by fermentation?
EtG is only detected in urine when alcohol is consumed. This is important since it is possible to have alcohol in urine without drinking. Alcohol in urine without drinking is due to the production of ethanol in vitro. Ethanol in vitro is spontaneously produced in the bladder or the specimen container itself, due to fermentation of urine samples containing sugars (diabetes) and yeast or bacteria. Since the ethanol produced is not metabolized by the liver, EtG will not be produced and will therefore not be detected in a urine containing alcohol as a result of fermentation.