Frequently Asked Questions
FAQ - see blog for more Q and A
Question?
Are there rules that can help interpret EtG/EtS testing?
Answer:
Scheme to help interpret EtG/EtS tests:
- Urine alcohol positive with negative EtG and EtS = suggests fermentation (in-vitro) - doesn't suggest drinking
- Urine alcohol positive with positive EtG and negative EtS = could be from fermentation and in-vitro synthesis of EtG, but could also be from drinking or incidental exposure
- Urine alcohol positive with negative EtG and positive EtS = suggests in-vivo alcohol - either drinking or incidental exposure
- Urine alcohol negative with positive EtG and/or positive EtS = suggests in-vivo alcohol - either drinking or incidental exposure
Question:
Positive EtG - Negative EtS??
How could EtG be positive and EtS be negative. Isn't that backwards?
Answer: It's interesting that in studies that have measured both EtG and EtS after drinking alcohol both are usually present but either one can be absent occasionally. That is why it is best to check both. If either one is present it's a strong indicator for probable drinking. We have better information on why EtG can occasionally be absent (ie due to bacterial breakdown but it's also thought that EtG is occasionally absent because of genetic absence of some of the enzymes that are used to make EtG). Likewise when EtS is absent and EtG is positive it's thought to be due to genetic variations leading to reduced or absent enzyme systems needed to make EtS. Bottom line: If either EtG or EtS is present a "big red flag goes up" indicating probably recent drinking.
Question:
Re cutoff levels - from an MRO?
Wondering how you would respond to the comments on the discussion list that there can be incidental exposures with levels above 1000. I am dealing with a donor who claims that her only exposure after checking all bottles and ingredients in her house was using Preparation H on a raw area. She indicated the label noted 7% alcohol. Her level was 700. I have no problem with EtG levels about 1000 in general but starting to be a bit concerned about those in the 500-1000. I know there have been a few studies on "tea-totalers" but... even with the Vicks, dilutes, and poppy seed issues, the problems were not picked up until large number of tests were done.
Answer:
We agree with you regarding the large population studies needed to clarify these issues. The ubiquitous "bell shaped curve" seems to come into play. Studies need to be performed to test the limits of these phenomena. The problem with setting an upper limit for EtG that could be secondary to "incidental exposure" is that there is no clear definition of what could be considered the upper limit of "incidental exposure." I recently testified in a board hearing where an individual claimed "incidental exposure" from accidentally drinking spiked punch, and in another where the participant claimed a positive test from 100 times more tincture of ginko-biloba than recommended, and another where a physician in recovery was using a bottle of vanilla extract in a thermos of coffee per day. In all these hearing the boards eventually allowed these explanations as cause for incidental exposure. The EtG levels were between 800-5,000ng/ml. Therefore, it appears that if we can't define the limits of incidental exposure, or multiple incidental exposures in an individual, then we certainly won't be able to set an upper limit for EtG that could be caused by that exposure.
From a practical point of view any EtG over 100ng/ml means there has likely been exposure to ethanol. I would encourage anyone confronting a donor who has a positive EtG to approach them in a non-confrontational way but affirmatively certain that there is proof of drinking and encouraging them to accept help. When utilizing this approach approximately half have admitted beverage alcohol exposure. I think the initial approach to confronting the individual has much to do with the outcome. We don't currently know the limits of what could be produced from "incidental exposure," however; if everything else in their monitoring looks good, they deny alcoholic beverage use, and some likely source of incidental exposure is identified then it is wise to consider the alternative explanation.
Some things I've recommended when a positive test leads to a convincing denial of drinking are: 1. Obtain a creatinine on the urine so a U100 Creatinine can be deterimined to identify the influence of concentration, 2. If there is a suspected source of incidental exposure it can be tested to see if exposure to this item causes a positive (most of these have been negative), 3. Obtain an evaluation where a polygraph could be performed, 4. Start the participant on antabuse (preferrably observed administration at 500 mg/d), and finally, 5. Have the participant wear a SCRAM device (transcutaneos alcohol sensore) as a corroborating detection method.
Question?
Supervising a testing program?
I run a testing program. It looks to me like coming up positive in the 100 range could be incidental usage? If so there is there any other advice I can give my testers other than "don't use cough medicine or mouthwash"?
Answer:
A couple thoughts for you:
1. It's a good idea if you are going to use EtG monitoring be sure there is a clause in their monitoring agreement stating that they agree to: "no alcohol of any kind including alcohol in foods, hygiene products, or OTC meds containing alcohol (eg vanilla extract, mouthwash containing alcohol, nyquil, cough syrups, etc), no communion wine, no topical gels or medications containing alcohol on skin or mucous membranes, etc.. I agree to avoid all alcohol containing products and understand that use of any of these products cannot be used as a defense to a positive urine drug test and will be considered a violation of this agreement."
2. We have studied use of products such as alcohol containing mouthwash on small numbers of subjects and have found positives as high as 700.
Question?
Re hand sanitizers containing ethanol?
"We were wondering about the use of alcohol based hand sanitizer which we use countless times per day and the effect on EtG. We tried to research it on the Internet, and it says that it is absorbed by the body, however it stated that studies on those in recovery have not been performed. Could you please let me know your thoughts on this? Thank you for your time."
Answer:
Yes. We were concerned to evaluate alcohol gels that have a high content of ethanol (>60%) and are commonly used in hospitals and elsewhere. Further evaluation is underway. It appears that inhalation of the vapor from ethanol hand gel does cause elevated EtG and EtS levels. These levels can be surprisingly high.
Question?
Differences between men and women?
Looking at superimposed graphs of blood alcohol levels from one drink in a men and one drink in a women, the women will have a higher blood alcohol level. Is this true also with the ETG levels? Theoretically, a women would have higher blood alcohol levels with incidental use also, and therefore higher ETG results. If this is true, shouldn't the cut-off levels be different for male and female?
Answer:
This has not been specifically examined. There appears to be much variation in how much EtG one individual produces compared to another (due to polymorphism of the enzyme systems), which is probably a more significant factor. Also, because it is thought that less than 0.1% of alcohol is metabolized into EtG, and because of urine concentration/dilution factors, time frame, etc, It is doubtful that it will be possible to have exacting precise cutoffs. In other words, the cutoff levels will need to be fairly high anyway and will probably not be greatly affected by slight changes in serum alcohol levels. However, time will tell, as more research is performed.
Question?
Positive urine alcohol and negative EtG?
We've had a few instances of positive urine alcohol (low levels) and negative ETG. We are suspecting perhaps our lab cut off for urine is lower and more specific, than the cut off for ETG. What do you think?
Answer:
Urine EtG (and even better EtS) is actually more "specific" than urine alcohol since alcohol can be present in urine without drinking (if it ferments there) but the most likely reason to have EtG and particularly EtS in the urine is if alcohol has been present in the body. So there are really only three reasons you can have a positive urine alcohol and negative urine EtG and EtS. 1. The alcohol fermented "in-vitro" in the urine, 2. The urine was obtained very soon after drinking, since it takes EtG longer to appear in urine than alcohol, or 3. The cutoff value for EtG and EtS is too high.
In the case of #1 there is evidence that not only can yeast ferment alcohol but also some bacteria and the amount of glucose neccessary can be small. So it's not just in diabetics with yeast in the urine that fermentation occurs. In the case of #2 it doesn't make much sense that someone would drink and then give a urine sample within 1 hour. In case #3 some labs are setting the cutoff for EtG high to avoid positive EtGs from "incidental alcohol use" and this would making EtG less sensitive.
In conclusion, we are using a 100 ng/ml cutoff and if the urine is positive for alcohol but negative for EtG and EtS we are assuming it was probably in-vitro fermentation (ie a false positive test). Nevertheless we still confront the participant and ask them if they've been drinking but we drop it if they deny drinking.
Question?
EtG stability - warm weather?
Does warm weather during shipment cause a more rapid breakdown of EtG in urine?
Answer:
Maybe, but it's not clear. Recent experiments show that heating urine to 100 C (boiling point of H2O) actually increased the stability of EtG. The data are showing that at room temperature, in some individuals with nitrites and/or blood in urine, that EtG can deteriorate over a week. We are surmising that esterases associated with infection may be causing breakdown of EtG. Heating seems to prevent breakdown, possibly due to neutralizing the bacteria. So, the fact is that heat doesn't cause breakdown of EtG, it actually increases stability. It is possible, however, that bacteria would grow more rapidly in warmer weather (closer to body temperature) and it has been shown now that bacteria can breakdown EtG (but not EtS).
Question?
Questions concerning the AWOL vaporizer:
This “new” method of alcohol abuse known as Alcohol Without Liquid (AWOL) vaporizer is discussed on the web sites www.awolmachine.com Following is the response from Dr. Ed Barbieri from National Medical Services, Willow Grove PA:, regarding an opinion about how this would affect EtG.
Answer:
”We have looked into the AWOL machine from the website. Alcohol may enter the bloodstream in the manner that is described on the web site. For ethanol to get to the brain it MUST enter the bloodstream. If ethanol enters the bloodstream, it will be distributed to other tissues throughout the body including the liver and, therefore, will be metabolized. Once metabolized, ethylglucuronide can be formed and will be eliminated (along with some ethanol) into the urine. In summary, if someone is choosing to take in ethanol in this manner, it will still be metabolized through traditional pathways that may result in positive EtG findings. The EtG results would be dependent upon the time from exposure, amount etc., all of the same things that would need to be considered if alcohol was ingested in a liquid form through drinking.”
Question?
Incidental exposure to ethanol in the environment?
What about incidental alcohol use, such as in food, mouthwash, communion wine, etc?
Answer:
This is an important question and an important issue to understand. Ethanol, unlike other drugs, is fairly ubiquitous in our environment. It's in food (ie vanilla extract). It's used as solvent in "over-the-counter" meds. It's used in ceremonies (ie communion, etc). It's virtually present at some level in everything that contains glucose. It is recommended that anyone being tested (i.e. those in monitoring following alcohol problems) be advised that they should not consume food containing significant alcohol, such as avoiding OTC meds containing alcohol, mouthwash with alcohol, and/or communion wine or anything else containing significant alcohol.
Question?
Reliability and legal status of EtG testing?
Is EtG dependable enough to rely on a positive determination to take legal action, such as revoking a license?
Answer:
EtG appears to be highly specific, similar to testing for other drugs. However, no forensic toxicology test is 100% reliable. Therefore, we strongly recommend that for all urine tests found to be positive in which the donor denies drinking that caution be used. Someone who understands this test in great detail should be involved in assisting interpretation. Feel free to contact us (see contact information above).
Question?
Confirming positive urine alcohol by EtG testing?
Should an EtG always be performed to confirm a positive urine alcohol test?
Answer:
Urine alcohol as an indicator of alcohol consumption can be falsely positive secondary to in-vitro fermentation. Therefore, traditionally, whenever there's a positive urine alcohol, labs have examined the specimen for glucose and yeast, which can suggest the possibility of fermentation. However, the presence of glucose and yeast doesn't prove the individual did not drink alcohol. In addition to false positives from fermentation, there's also been a question of positive urine alcohol tests due to "incidental" alcohol exposure (i.e. mouthwash, food, otc meds, etc). There is no data on this subject.
In-vitro fermentation can cause a positive EtG because bacteria can in some situations metabolize alcohol into EtG. This has not been shown with EtS, proving the importance of performing EtS and EtS together whenever possible. Testing all positive urine alcohol samples for EtG and EtS makes sense.
Here is a suggested protocol: For a positive urine alcohol, confront the individual regarding the positive test. If they admit to drinking alcohol, of course you don't need to test further. If they deny use, perform an EtG/EtS on the sample. If the EtG and EtS are negative, consider the urine alcohol a false positive. (This doesn't actually prove it is a false positive, however, it substantially increases the likelihood.) If the EtG or EtS is positive, let them know you now have further proof they consumed alcohol (a positive urine alcohol and a positive EtG or EtS). The manner of approaching them in this situation matters. Using language such as, "We now know you did drink alcohol and it's very important you face this, be honest, and allow us to assist you before it gets worse...".
Greg Skipper, MD gregskipper@usa.net
Question?
EtG and CLIA?
Is EtG waived for CLIA?
Answer:
There is no test for EtG that could be performed in an office setting. It is not CLIA waived.
Question?
Cutoff levels?
Why are cutoff values different from different labs?
Answer:
Re cutoffs values: The primary cutoff is a lab procedure to assure technical accuracy of the test. Depending on the technique and its accuracy the cutoff level reduces potential error from intrinsic variations from the test procedure. For these purposes labs believe they can substantiate the quality and validity of testing using a cutoff of 100 ng/ml. There is always a tension between sensitivity and speicificity, false positives and false negatives. The cutoff values should not be so low that the test picks up extraneous alcohol intake (food, mouthwash, etc) resulting in "false positives." On the other hand it is not desirable for the threshhold to be too high, which reduces sensitivity, and would create more false negatives.
Also, we know that very little alcohol (.02-.06%) is metabolized by non-oxidative glucuronidation. The "standard drink" in the USA is 14gm (about 1.5oz of vodka, 12oz beer, 5oz wine). Thus the small fraction of alcohol actually metabolized this route means that a significant amount of alcohol would have to be consumed to register positive even with a cutoff of 100 ug/L.
Based on a single exposure study where a man was given about 1 oz of alcohol it was shown that EtG was detected for about 30 hours with no "cutoff." If the cutoff were 250, EtG would have been detected for about 14 hours after the drink. If the cutoff were 100, EtG would have been detected for about 25 hours. Thus you can see how much better the 100 cutoff is, with almost twice the "time of detection," which is why EtG is valuable in the first place, to try and extend the detection time.
The 100 ng/ml cutoff is better for monitoring purposes, as long as clinical judgement is used in assessing the meaning of positives. More research and testing are underway and more data is needed and hopefully will be available soon.
Question?
EtG stability - cooking, etc?
Is EtG heat labile? (ie Does a positive EtG and a negative alcohol suggest cooking with alcohol as a source or just a lower level of exposure?)
Answer:
Eating food cooked with alcohol (wine etc.) can lead to significant alcohol exposure (ie not all the alcohol is "cooked off"). Therefore, cooking with alcohol can be just like drinking alcohol. Alcohol doesn't last long in the body, howeer, which is why EtG and EtS testing are valuable. Therefore, cooking with alcohol can easily resut in a negative urine alcohol but positive EtG or EtS. A low level of EtG or EtS can mean low level of alcohol exposure or that you tested further from the time of exposure. Level of EtG or EtS cannot predict amount of drinking. There are too many confounding variables.
Question?
Medications causing false positives?
Are there any meds that would give a positive EtG?
Answer:
So far only ethyl alcohol seems to produce EtG or EtS. The issue is really more where did the alcohol come from? Many medications include ethanol as a solvent (cough syrup, etc) and therefore could cause a positive EtG or EtS..
Question?
Polyethylene glycol and EtG?
What about polyethylene glycol? Can it cause a positive EtG?
Answer:
Probably not but there have been no studies to our knowledge! Polyethylene glycol can be found as an ingredient in various tablets and OTC meds. There is no evidence that degradation of this compound produces ethanol, especially in enough quantity to cause a positive EtG or EtS test, however, ideally it should be studied. Another compound that should be studied is ethyl chloride, used as a spray for sore musces.
Question?
Does the cutoff need to be increased? If further research has shown some individuals producing higher quantities of ETG with incidental use, and the difficulty having a precise exact cut-off, will this change the current cut-off levels? How can it be assured the positive value of >100 or >250 (as currenty used) is from actual beverage alcohol intake? Is it possible the cut-off levels will change considering this new finding?
Answer:
There is no known cutoff that distinguishes between drinking alcohol and other exposures to alcohol at this time. What we are likely going to have to live with is that EtG and EtS are "red flag" markers of likey alcoholic beverage use, as this is the most likely source for adequate alcohol to cause positive tests, however, they are not proof of drinking. They should trigger confrontation (if alcoholic beverage use is admitted - end of story) but if alcohol use is denied then more careful monitoring and observation and/or possible antabuse administration should be considered.
Question:
Please clarify for me the units of measured urine EtG levels. In the discussion of incidental exposure, you refer to 100-500 micrograms/liter as being possible incidental exposure but that it would unlikely be incidental at > 500 micrograms/liter. Then in a later discussion regarding laboratory cutoffs you refer to 100 mg/liter. Since the difference here is huge, I ask that you please clarify. In other points in your presented literature and discussions you also refer to nanograms/ml which would be equal to to micrograms/liter. The use of different unit values makes it very hard to draw conclusions. Thank you for the opportunity to read all the information presented in your web site.
Answer:
Yes, the difference is 1,000. Sorry, there was an error. I've now corrected it. Some of the confusion stems from the fact that the European literature uses lower figures. For example in the European literature .4 mg/L or = .4 ug/ml and in the USA the same amount would be expressed as 4000 ng/ml or 4000 ug/L.