A Positive EtG and/or EtS Alone Does Not Confirm Drinking
There is currently no known cutoff for a positive EtG or EtS that confirms drinking. Before enumerating the reasons it’s important to know, however, that statistically most positive EtG/EtS levels are due to drinking, probably 90% or more, however, there are a significant percentage of positives not due to drinking and therefore a positive EtG/EtS doesn’t prove drinking. The higher the EtG/EtS level, especially if corrected for concentration, the more likely the positive was due to drinking. In other words, low level positives (under 2,500ng/ml) can occur more often from incidental exposure to alcohol but there’s no proof that levels above this could not also be from incidental exposure or combinations of exposures.
There are two issues: Does a positive EtG/EtS prove drinking and can setting a cutoff level distinguish between drinking and other causes of positives?
First: Why a positive EtG/EtS does not prove drinking:
Incidental sources of exposure to alcohol are numerous and can be found in mouthwash, over-the-counter medications (cough syrups, Nyquil, etc), communion wine, alcohol-free wine and beer, foods (foods cooked with wine or fermented items, beverages containing sugar that have been opened and may have fermented, etc), and vapor of alcohol (from hand gels, perfumes, bug spray, gasohol, etc) and others. All of these sources can cause a positive EtG and their effects are additive.
Alcohol can be produced inside the body if someone consumes yeast (such as baker’s yeast) and sugar (such as in drinks or foods). This small amount of alcohol is metabolized into EtG and EtS.
Second: Why is there no cutoff that clearly distinguishes between a positive EtG/EtS from drinking and incidental exposure.
Concentration
Normal urine can vary up to 20 fold in concentration. The more concentrated urine will report 20 times higher EtG/EtS levels than more dilute. Concentration of urine can be inferred from the urine creatinine levels. High creatinine means concentrated urine. Low creatinine mans dilute urine.
Variations in individual’s production of EtG
The enzymes that turn alcohol into EtG and EtS are determined by genes and there is more than one enzyme and more than one gene, therefore, people can vary considerably (from none to excessive) in the amount of these metabolites produced. Foods, vitamins, illnesses, etc, can affect the enzymes and can cause variation in the level of EtG, from much higher to lower. It has been estimated that between .02 and .4 percent of alcohol is metabolized to EtG, depending on the individual. This is a 20 fold difference and can result in a huge variation from a given exposure.
Lack of adequate scientific studies
All studies to date that have looked at levels of EtG/EtS from exposure to alcohol have been in very limited numbers of people. In biological systems there can be great variation over larger populations. Larger studies, involving many subjects will be necessary to determine these variations. These type studies have not been conducted.
There are two issues: Does a positive EtG/EtS prove drinking and can setting a cutoff level distinguish between drinking and other causes of positives?
First: Why a positive EtG/EtS does not prove drinking:
Incidental sources of exposure to alcohol are numerous and can be found in mouthwash, over-the-counter medications (cough syrups, Nyquil, etc), communion wine, alcohol-free wine and beer, foods (foods cooked with wine or fermented items, beverages containing sugar that have been opened and may have fermented, etc), and vapor of alcohol (from hand gels, perfumes, bug spray, gasohol, etc) and others. All of these sources can cause a positive EtG and their effects are additive.
Alcohol can be produced inside the body if someone consumes yeast (such as baker’s yeast) and sugar (such as in drinks or foods). This small amount of alcohol is metabolized into EtG and EtS.
Second: Why is there no cutoff that clearly distinguishes between a positive EtG/EtS from drinking and incidental exposure.
Concentration
Normal urine can vary up to 20 fold in concentration. The more concentrated urine will report 20 times higher EtG/EtS levels than more dilute. Concentration of urine can be inferred from the urine creatinine levels. High creatinine means concentrated urine. Low creatinine mans dilute urine.
Variations in individual’s production of EtG
The enzymes that turn alcohol into EtG and EtS are determined by genes and there is more than one enzyme and more than one gene, therefore, people can vary considerably (from none to excessive) in the amount of these metabolites produced. Foods, vitamins, illnesses, etc, can affect the enzymes and can cause variation in the level of EtG, from much higher to lower. It has been estimated that between .02 and .4 percent of alcohol is metabolized to EtG, depending on the individual. This is a 20 fold difference and can result in a huge variation from a given exposure.
Lack of adequate scientific studies
All studies to date that have looked at levels of EtG/EtS from exposure to alcohol have been in very limited numbers of people. In biological systems there can be great variation over larger populations. Larger studies, involving many subjects will be necessary to determine these variations. These type studies have not been conducted.
