I am a 24 yr old female 5'4 130lbs. I drank Thursday night from 8pm 12am. I drank a half pint and 3 beers. I have to take an EtG test Monday at 10 30 am. With all the different information out there about this test I'm really confused on if ill pass or not. It will be about 82 hours from my last drink until I take my test. Any clarification on this would be appreciated. Thanks

So that you and those subjected to or relying on this test better understand.

EtG testing does not detect small amounts of alcohol for 80 hours or 5 days as frequently represented by the commercial testing labs. The 120 hour claim is without scientific support and even the 80 claim applies only to exceptional cases involving very heavy and usually long-term drinking.

EtG and EtS are direct metabolites of ethanol (EtOH). As you eliminate EtOH from your system EtG is created as a by-product. That means that it is created in relation to the amount of systemic EtOH present. As example, the EtG created by one drink will be eliminated in under 24 hours, two drinks in about 26-31 hours, three drinks in about 30-41 hours, etc.

EtG is not cumulative and follows a similar elimination curve with EtOH albeit at a slower rate.

You consumed 7.5 standard drinks (US) in a 4 hour period.

Based on your size and gender that would result in a BAC possibly as high as .20. (range .14-.20)

Elimination time for the EtOH would be in the range of 8-11 hours (based on .018 per hour)

The reason BAC is considered is because so long as EtOH is being eliminated EtG is being created while at the same time EtG was eliminating from earlier drinks, but at a slower rate than EtOH.

At any rate we now subtract the time for EtOH metabolism and you are left with about 71 hours for EtG clearance.

Based on your size and gender, calculating from BAC=0 average EtG elimination would be in range of 56-66 hours*. However, there were about 3 of 32 that were positive up to 78 hours.

Therefore, the odds are that you will not have measurable EtG, but it is possible.

*none of the EtG elimination studies distinguish M from F even though it is well known that F metabolize alcohol about 10% faster than M.

Ref.

Wojcik & Hawthorne, 2007
Helander, 2009