Dr. Bill, I noticed that most of the studies that you cite when answering questions on this forum have an EtG cut-off of 100 ng/mL. Do you have any information regarding an EtG cut-off of 500 ng/ML? How does this higher cut-off change some of the estimates you have made for people here? Thanks!

I can see that you have done your homework. The variance in cutoff levels is indeed confusing. Add to this the fact that most of the studies use different methods to determine elimination time and you are pretty much on your own in comparing results from study to study.

However, using the studies that display graphs you can make some reasonably valid estimates. As example see:
Hoiseth, 2008 (http://alcalc.oxfordjournals.org/content/43/2/187.full)
Wojcik & Hawthorne, 2007 (http://alcalc.oxfordjournals.org/content/42/4/317.full)
Helander, 2008 (http://alcalc.oxfordjournals.org/content/44/1/55.full.pdf+html)
Rosano & Lin, 2008 (http://www.burlingtonlabs.com/documents/ETGPublicationJATvol322008_000.pdf)
Sarkola, 2003 (http://alcalc.oxfordjournals.org/content/38/4/347.full)

Even then you must be attentive to detail and note baseline. Is it 0 (absolute level of detection) or based on a fixed cutoff, 110, 250, 500? Measure accordingly.

There are various estimates as to the proportion of samples testing positive from one cutoff to another, however these are in my opinion questionable:

Raising the cutoff from 100 to 250 (http://www.expertdrugtesting.com/content/view/32/1/) will cut in half the number of positives.

Quest Diagnostics, reported in Toxicology News (http://www.aacc.org/SiteCollectionDocuments/Publications/cftn/CFTn_Dec_2006.pdf), in an evaluation of 70,000 EtG screens, of those that were positive, 24.2% were detected between 100-250 ng/mL, 15.8% between 250-500 ng/mL, 12.6% between 500-1,000 ng/mL, and 47.7% greater than 1,000 ng/mL. These statistics translate into a 24.2% drop in the positive rate if the cutoff is raised from 100 to 250 ng/mL and a 40% decrease if it is raised from 100 to 500 ng/mL. Based on a review of positive samples retested by Quest Diagnostics, contained in Clinical & Forensic Toxicology News, 2006.

Subsequently Redwood Toxicology (http://www.gtfch.org/cms/images/stories/media/tk/tk78_2/mosbach2011abstsatsymp.pdf), reported in Toxichem Krimtech 2011;78(2):9 re-tested a large number of sample and found "Assuming the positivity rate to be 100% with an EtG cut off 100 ng/mL, a cutoff of 250 ng/mL detects 91.4% of the positives, 500 ng/mL cut off detects 78.1%, 1,000 ng/ml cutoff detects 63.8% and a cutoff of 2,000 ng/mL detects 51.1% of the positives in a given population.

Finally, in the elimination studies, you must be aware of how often the samples were collected. In most of the studies showing long-term detection, urine samples were collected once each 24 hours. That is an unacceptable time span. Could result in errors from 1-23 hours is elimination time.

In direct response to your query there is no standardized method for making the comparison you cite. It's all a matter of cumulative comparison. My method is conservative and I extrapolate from a 500 cutoff to 100 by reducing window of detection by 20%.

Hi DrBill I had a pint of vodka mixed with 7up soda on Friday I stopped by midnight and I'm testing on Tuesday 1pm EtG test it been 84 hrs from my last drink You think I will pass with that amount of alcohol in that period... and soon I get my test back I will let you know if I passed or not... im a male weight: 158 height 5'10...

A pint (375 mL) contains 8.5 standard drinks (US). You will probably pass but you're in an area that has little research.

Over what period did you consume the pint? You stopped at midnight, when did you begin?

I started at 8:30PM SAME NIGHT...

I would be surprised if you test positive, but you probably were making EtG until 6 am or so Saturday. That leaves you about 79 hours after BAC 0. While it is possible to test +, it isn't likely-especially if the cutoff is 500.

RNBSN is correct. The problem with estimating EtG elimination in your case is 1) the amount of alcohol consumed and 2) the relatively short period for consumption, 2-1/2 hours. That tends to raise the BAC and possibly the amount of EtG created.

It is very unusual for EtG to be detected above 72 hours, but it can happen in about 20% of cases.

Very interested in your results.

I will let you know

I passed thanks guys

Dr, my boyfriend consumed maybe 5 or 6 beers on a Monday and got drug tested the next day. He started drinking around 8 and stopped at 1030. He did not pass the drug test. The cut off was 1000 ng/mL. I'm confused about the 1000 ng//mL. can you explain it to me and is there a way to fight the results?

Dr, my boyfriend consumed maybe 5 or 6 beers on a Monday and got drug tested the next day. He started drinking around 8 and stopped at 1030. He did not pass the drug test. The cut off was 1000 ng/mL. I'm confused about the 1000 ng//mL. can you explain it to me and is there a way to fight the results?

The amount of alcohol that he consumed would take ~48+ hours to drop below 1000ng. Do you know the level of EtG that showed up in his urine?

1000ng is a fairly high cutoff when compared to 100, 250 or 500ng. That just means that 1000ng cutoff greatly reduces false + results and would eliminate most excuses regarding incidental contact.

Dr. Bill you seem to know what your talking about. Do you know how long it takes To get a test result back and be notified? This may be out of your area of expertise, but whatever you can tell me would be deeply appreciated. I had my test 2/7/13 and today is obviously the 12th.