Would one pint of vodka trigger a positive PEth test if drank once weekly on two consecutive weeks with the latest drink a week prior to testing? Otherwise no prior alcohol consumption for several weeks.
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Would one pint of vodka trigger a positive PEth test if drank once weekly on two consecutive weeks with the latest drink a week prior to testing? Otherwise no prior alcohol consumption for several weeks.
Older studies indicate that PEth is an indicator of sustained drinking whether by episode or duration. You posit consumption of "pint" equalling 8.5 standard drinks during a one week period. Whether consumed across a 7-day period or within a singular drinking episode that amount should be detectable via PEth.*
I am currently researching this subject via request of another member (see LINK)
PEth testing has not been widely used in US, research is limited, therefore please accept my advice accordingly.
*this amount is disputed.
How long would this amount remain detectable?
Not sure. The tested time lines are all over the board ranging from 1-4 weeks. It seems that the longer times derive from continuous heavy drinking over a long period.
There are several newer studies that are using LC-MS/MS as opposed to the older HPLC test. The sensitivity of the instrument would provide a longer detection period.
To the best of my knowledge there are currently only a couple of labs offering the test.
Who are you working with that is requiring the test?
Was actually tested last week by a disability insurance company I am applying fir insurance with. They sent a nurse out to take blood and urine to look for all kinds of stuff including PEth to rule out problem drinking. I put drops of blood on a card for the PEth. Not sure which lab they use. Have not heard about results so maybe no news is good news.
The test was from USDTL (Desplaines, IL) PEthStat. It's a dried blood spot (DBS) test. You can brush up on it here. > LINKQuote:
Originally Posted by Mtb2013
When reading the number of drinks and the grams required to create detectable PEth, keep in mind that one drink contains 13.7g of pure alcohol. The description of the test doesn't follow.
When you say the description of the test doesn't follow, what do you mean?I calculate about 140g, below the 200g they cite.
They state 200 at one point and continue to say that one drink per day for 6-7 days. That is under 100g.
There are other studies that indicate a single high consumption is not detectable, but requires about 50g per day across about a 3-week period. Helander 2009
If it's done by mass spec(rather than HPLC), it can detect *very small*(I mean a single drink) consumption over a few week period... whether or not the test is set up at that level of detection is another question.Quote:
Originally Posted by DrBill100
If it's done by HPLC and the lowest typical cutoff is used, most of the best data suggests that you need > 700grams...
I think, in the future, PEth by mass spec is going to be *the* test that puts an end to closet timed drinking in the monitored populations... with urine EtG you can time it right if you're not tested on weekends ever. With blood PEth by mass spec, those days are theoretically over...
Hasn't LC/MS been used in more recent research?Quote:
If it's done by mass spec(rather than HPLC), it can detect *very small*(I mean a single drink) consumption over a few week period... whether or not the test is set up at that level of detection is another question.
I agree that there is increasing interest in PEth but the procedural barriers are very significant in drawing and handling samples. It also limits the labs that can participate.
Im actually a basic science/lab idiot, so you know much more than me... I may have even misspoke.
I do know that the levels of detection now possible in detecting PEth are ridiculously low. I know this because I saw another person's report where he got nabbed by a random PEth with a level of like 100 or so NANOmols/l. IOW, way way less than a lot of the lower limits of detection some of the studies were done on many years ago.
In this state(I'd rather not say which one) they are now monitoring health professionals randomly about every year with PEth. I guess they are just using it to fill in the gaps with EtG urine testing. If someone drinks a beer or two on fridays after work once or twice a month(and thus won't get caught with EtG testing), it is almost certain that he will get nabbed by PEth.
Could you speak more about procedural barriers with PEth in drawing and handling samples? My impression was always that an etoh positive sample is problematic to make much of a PEth level from(for obvious reasons), but when PEth is being used to confirm absolute sobriety in zero tolerance programs(and not as a measure of excessive drinking), how is that a problem?
Im sorry I misspoke... it was a good bit lower than that I recall.Quote:
Originally Posted by hemp934
By procedural I was referring to sampling, storage, transportation. Currently the testing procedures used, urine v blood, hair v. blood, etc are based on ease of sampling, storage and transportation and little to do with testing result. These samples can be obtained by the untrained, on site, then stored and shipped at ambient temperature. All of that relates to the economics of drug testing.Quote:
Originally Posted by hemp934
PEth requires a blood draw and that is a medical procedure. It cannot be stored or shipped at ambient temperature.
I believe another problem with PEth is the detection window and think that is less related to instrumental sensitivity than PEth creation. It strikes me that PEth is only created after continued exposure of the red blood cells (RBC) to circulating ethanol. Therefore it is a dose dependent and requires sustained exposure. A single or low level exposure would not result in PEth (which is an abnormality and not metabolite). If that is the circumstance then instrumental sensitivity is only of very limited concern.
In other words, if PEth isn't there it can't be detected regardless of the instrumental sensitivity.
Please don't view this as a disavowal of your observations. I've been reviewing PEth for about a year or less and view all of the current literature as inconclusive. Haven't dedicated a great deal of time to it as I believe it interferes with the economics of drug testing and therefore won't be widely promoted. So always interested in the viewpoint of others.
USDTL* has developed an interesting system analyzing dried blood spots for PEth. Currently that is a laboratory developed practice, but if commercialized could seemingly overcome the various problems I noted.
*United States Drug Testing Laboratory, Des Plaines, IL
Labcorp does blood draws for like 15-20 bucks... which is less than it costs to take a 1.5cm hair sample. Most state monitoring programs make a participant sign a contact allowing them to test for hair, urine, blood and saliva.Quote:
Originally Posted by DrBill100
I agree that something like PEth is useful or practicle for large scale screenings, but as an occasional(ie every six months) random for highly monitored populations(physician/pharmacy monitoring programs), it does have utility, and is already being used in at least one of these programs(the one I am most familiar with). The cost of transport and the test itself... well, the participant is paying for it. Also, as you mentioned, the cards are now out, and there is at least one lab now doing those(the person I know of who failed a random PEth had it done not through this method though)
Im interested in the science of PEth though... for a single exposure, what is your best guess as to the total amt in grams of etoh required to produce ANY? Papers I've seen have given different ranges.
That is the over arching question that remains to be answered. Just how much ethanol and for what period before PEth is induced (or results). I believe PEth must be directly related to macrocytosis wherein RBCs are enlarged and become less pliable. But that, like PEth, is associated with heavy drinking and is generally measured by mean corpucular volume (MCV) which has been used for some time as an indirect and not very specific biomarker of excessive drinking.Quote:
Originally Posted by ;
I really don't have any idea of the ethanol concentration required or the time of RBC exposure. I have yet to see any research indicating low level ethanol can result in either.
Additionally I haven't put much effort into reviewing time span for MCV to see if PEth is simply another manifestation of the same phenomenon.
Earlier in the thread you wrote " It strikes me that PEth is only created after continued exposure of the red blood cells (RBC) to circulating ethanol"... I've been trying to find something explaining the science/reason behind this, and any relevant studies. Could you point me in such a way or just explain why that would be the case? If alcohol is present and the enzyme has a 1000 fold greater affinity for alcohol than water, why does that exposure to create any PEth have to be "continued" exposure?Quote:
Originally Posted by DrBill100
It's going to be tomorrow when I can get back. In the meantime, the most definitive research seems to be coming from Karolinska Institute and Anders Helander in particular. You might want to Google "Helander, PEth"
Dr. Bill,
I glanced back at the thread and am interested in some of the feedback. By the way I never got notification of any bad results on my PEth test so I assume I passed. Do you know what type of instrument is used to process pethstat? I assume it is qualitative not quantitative unless each bloodspot is exposed to a higher level of developer to identify different quantities. If so, to what cutoff are they testing?
PethStat (dried blood spot) seems to be a proprietary test offered only by USDTL. By FDA standards this is classed as a laboratory developed test (LDT) and requires no pre-market approval so long as it is not sold to sources other than their customers. So there is no filing that describes the practice that I know of. I'm sure it would involve reconstitution and a low level analysis similar to LC/MS/MS.Quote:
Originally Posted by Mtb2013
LDT exclusion is being phased out by FDA but this test would be grand-fathered I imagine. AACC and LDT
just to follow up on this PEth thread... it appears that Louisiana's health monitoring programs have now started doing some random(NOT confirmatory after a + urine etg) PEth testing. Florida has already been doing it. Texas has been very aggressive about doing them for even routine missed call in's, and I wouldn't even be surprised if they are now sprinkling a random PEth in there occasionally... these are just states I know of. There may be many more who are doing it as well. I suspect there are because these people(the directors of monitoring programs) all go to the same conventions and meetings.
don't know whether they are using the USDTL spot blood test, or getting whole blood.
I think this is going to become more and more common as a screening test. The two major drawbacks(cost and need for blood which is more invasive) aren't that important in professional monitoring programs because the participants have already signed an agreement stating that they will give blood and they also signed an agreement stating it is their responsibility to pay for any testing.
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