PEth (phosphatidylethanol) is a blood biomarker that detects recent heavy alcohol use.
It stays measurable for about 3 to 4 weeks, far longer than breath, urine, or saliva alcohol tests.
How It Works
Walk In
Quick Blood Draw
Results in 3-5 Days
Who usually gets this test
Most people come in for one of a few reasons: a custody case that needs documentation over weeks, not days. A recovery or monitoring program tracking sobriety. A court or legal requirement asking for something more rigorous than a breath test. Or just personal peace of mind, whether that's about your own drinking or someone you care about.
PEth vs. Breath and Urine Alcohol Testing
If you've looked into alcohol testing before, you've probably run into breath tests, urine tests, and now PEth, and it's worth understanding what actually separates them, because the differences matter more than people realize until they need one of these for something that counts. A breath test only covers the last few hours, useful in the moment, but it can't speak to anything beyond that.
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Urine testing, specifically the EtG test, extends that window considerably, out to about 80 hours, or a little over three days, which makes it useful for short-term monitoring but still leaves a lot of time uncovered if what you're trying to document is a pattern rather than a single incident.
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PEth is a different category of test entirely. Because it measures a biomarker that forms directly in your red blood cells after alcohol exposure, it stays detectable in your blood for roughly 3 to 4 weeks, sometimes longer with heavier or more sustained drinking. That's the reason courts, custody evaluations, and recovery or monitoring programs tend to ask for PEth specifically instead of a breath or urine test: those situations usually aren't trying to answer "did this person drink last night," they're trying to answer "has this person been drinking heavily over the past several weeks," and only PEth can actually speak to that.
What Does a PEth Blood Test Measure?
PEth isn't something your body makes on its own, it only forms after you've had alcohol.
When you drink, a small amount of that alcohol reacts directly with the phospholipids in your red blood cell membranes, and phosphatidylethanol is what gets created in that reaction. That's the whole reason PEth works so well as a marker: it's not measuring the alcohol itself, which clears your system in hours, it's measuring a byproduct your body only produces because alcohol was there, and that byproduct sticks around in your red blood cells for weeks instead of hours. The more you drink, and the more often, the more PEth accumulates, which is why the test is so good at telling the difference between someone who had one drink at dinner and someone who's been drinking heavily on a regular basis.
Where to Get a PEth Test in Mesa
Right here at Quick Test, on East University Drive at Power Road. Walk in Monday through Friday, no appointment or doctor's order needed, and we'll have you in and out with a standard blood draw. Your results are posted straight to your secure patient portal in 3 to 5 business days, ready whenever you need them.
Frequently Asked Questions
How much does a PEth test cost? $165 total at Quick Test Health Services.
How long does it take to get results? 3 to 5 business days, posted straight to your secure patient portal.
Will a few drinks show up on a PEth test? PEth is built to catch patterns of heavy or frequent drinking, not one glass of wine with dinner. If your result matters for something legal, talk through what the number means with whoever requested the test, that's their call to interpret, not ours to guess at.