I have read many articles about EtG testing. On one hand, I have read up to "80 hours" (I understand that is an extreme) but see that almost everywhere the EtG half-life is listed as 2-3 hrs. Ok, with that being said, either there is a ceiling to the amount of EtG that can be eliminated from the body, the amount of EtG for the 80hrs is extremely high, or the half-life quoted is incorrect. If my math is correct, let's say the person's EtG level is a very high 800,000 after it peaks (I read 4 hours after the last drink is metabolized). So, in 7 hrs after the last drink is metabolized the level would be halved to 400,000;
In 10hrs, 200,000;
In 13 hrs, 100,000;
16hrs 50,000;
19hrs 25,000;
22 hrs 12,500;
25hrs, 6,250;
28hrs, 3,125;
31hrs, 1,563;
34hrs, 781;
37hrs, 391;
40hrs, 195;
43hrs, 98;
This level is low enough to pass a 100 cut-off.

Can anyone tell me what I am doing wrong or how EtG can be >100, 80 hours after
The last drink is metabolized? Dr Bill, your help would be appreciated.

Superb observation. You've been doing your homework. Nonetheless, wouldn't recommend spending much time on half life considerations. It won't lead to individual predictability in elimination of EtG.

1) It isn't possible to determine how much EtG is produced in relation to a measured quantity of ethanol.

2) Metabolism (of ethanol) is genetically determined and standardly varies by a factor of 4x. The variation is attributed to the enzymes Alcohol Dehydrogenase (ADH) and Aldehyde Dehydrogenase (ALDH). Both of these enzymes are active in Phase I of ethanol metabolism. Both have genetic polymorphisms influencing individual variation

3) EtG results from late (Phase II) ethanol metabolism, dependent on Phase I, yet also subject to separate genetic influences, specifically polymorphisms controlling the production of UDP-glucuronosyltransferase (UGT), the microsomal enzyme responsible for the formation of EtG.

As a result, some people, regardless of metabolic rate, produce more EtG per given dose of ethanol than others. This variation is of enormous potential a variation of “200 fold”. One individual could have a low metabolic rate and at the same time be a “hyperproducer” of EtG.

4) Ethanol metabolism/elimination varies by dosage. That is one drink does not follow the same kinetic model as 10 drinks. At a certain point, seemingly tied to heavy and/or long term consumption, there is an additional metabolic system that kicks in, Microsomal Ethanol Oxidizing System (MEOS) [I call it liver overdrive]. This supposedly accelerates Phase I metabolism significantly. The interrelated inluence on EtG production (Phase II) has not, to my knowledge, been studied.

Combining the above, only very basic elements, any attempt to individually quantify EtG production/elimination by consumption/half life is, if not impossible, unproductive.

But please continue to read about EtG testing. The process needs close social and scientific scrutiny and your observations are correct: The facts don't comport with the conclusions.

Nonetheless, in more direct response to your question, I note that we have a couple of members academically qualified to address your more direct query in relation to interpreting half life: See DrBob1(https://www.askmehelpdesk.com/members/drbob1.html and Unknown008 https://www.askmehelpdesk.com/members/unknown008.html

I believe, as commonly applied, it is an inadequate model for alcohol metabolism. But, please, decide for yourself.

Should you need additional resources or references for EtG please let me know.

DrBill100,

Thank you for such a detailed answer. I am particularly interested because I have been a nurse for a while and know several nurses that are in recovery programs with their state's nursing boards. Without exception, even if alcohol was not their drug of choice, the EtG test is the test that is feared the most. I have seen nurses hold their breath when they use liquid hand sanitizer (many won't use it even though it is required by the hospital). Many avoid upscale restaurants because of fear that there may be wine in the sauce or alcohol in the soup. They even refuse communion. Before I read so many horror stories about nurses testing + for EtG, I thought that they were being over dramatic.

It appears that Dr Skipper intended EtG testing to be used to prove (at least suggest) abstinence from alcohol is occurring. However, EtG testing is being used to condemn rather than verify abstinence. The more I read about EtG variability, I believe that if the test is going to be used for the purpose of condemnation, at best, it should be ordered “for cause� testing when other evidence exists. The test should never be used as a screening test. If EtG testing is used as a screening test, it should take several + EtG test results before the HCP could be dismissed from their program. I understand that is not the case.

I do see that, used properly, EtG testing could be of value. But, given the current use of the test, my goal is to arm as many as possible with information that either comforts them or empowers them to confidently address their board should they test positive when they have not consumed alcohol. I will keep reading and posting.

A person with liver disfunction may metabolise more slowly, but the average person would clear in about 48 hours as you have calculated based on every journal article I have read. Many other factors have an impact, like the doctor above mentioned, but someone out there does take 80 hours; so to boost sales they make the claim. Personally I believe there are too many things that can create EtG like Listerine or hand sanitizer absorption or banana fosters to name a few. For this reason and the lack of understanding about individual metabolism I think this test should be banned from Prop 36 and PC1000 testing. People are going to prison based on this test or losing their jobs and credentials. The citizens need to stand up and complain.

http://www.kap.samhsa.gov/products/manuals/advisory/text/0609_biomarkers.htm

Even the substance Abusde and Mental Health services conclude this test should just be a screen and not the definitive to put you in jail or take your job.

http://alcoholism.about.com/b/2011/01/25/etg-alcohol-test-maker-faces-lawsuit.htm

[QUOTE=cyndikus;3400513] A person with liver disfunction may metabolise more slowly, but the average person would clear in about 48 hours as you have calculated based on every journal article I have read. Many other factors have an impact, like the doctor above mentioned, but someone out there does take 80 hours; so to boost sales they make the claim. Personally I believe there are too many things that can create EtG false positive like Listerine or hand sanitizer absorption or banana fosters to name a few. For this reason and the lack of understanding about individual metabolism I think this test should be banned from Prop 36 and PC1000 testing. People are going to prison based on this test or losing their jobs and credentials. The citizens need to stand up and complain.

The Role of Biomarkers in the Treatment of Alcohol Use Disorders

Even the substance Abusde and Mental Health services conclude this test should just be a screen and not the definitive to put you in jail or take your job.

ETG Alcohol Test Maker Faces Lawsuit