A PEth blood test in Mesa, AZ is a lab test that measures phosphatidylethanol, a marker that forms only after drinking alcohol and shows drinking over the past 2 to 4 weeks.
How It Works
Walk In
Quick Blood Draw
Results in 3-5 Days
What Is a PEth Blood Test?
PEth, short for phosphatidylethanol, is a substance that forms in your red blood cells only when alcohol is present. When you drink, a small amount of the alcohol reacts with the fatty layer of your red blood cells and creates PEth. Your body doesn't make it any other way, so finding PEth in your blood is direct evidence of alcohol use, not a guess based on liver numbers or other indirect signs.
That's what makes it different from a breath test. Alcohol itself leaves your body within hours, but PEth stays in your red blood cells for weeks and builds up the more often you drink. A PEth test shows a pattern of drinking over time, which is why courts, custody evaluators, treatment programs, and transplant teams rely on it.
Can a PEth Test Detect Occasional Drinking?
One drink, or a rare night out, often won't produce a positive result.
Usually not, and that's by design. A PEth test is built to show regular or heavy drinking, not a single glass of wine. In one study, people who hadn't been drinking for four weeks then had a single drinking session, some reaching a fairly high blood alcohol level, and none of them went over the standard 20 ng/mL cutoff afterward.
Regular drinking is different. PEth builds up with each drink, so drinking a few times a week, or several drinks a day, pushes levels higher. Research has linked about two to four standard drinks a day to the moderate range, and four or more a day over several days to the heavy range. A weekend of heavy drinking can show up too, especially if it happened in the last week or two. In short: the more often and the more recently someone drinks, the more likely PEth is to show it.
PEth vs. Breath and Urine Alcohol Testing
If you've looked into alcohol testing, you've probably run into breath tests, urine tests, and now PEth.
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. It's useful in the moment, but it can't speak to anything beyond that.
A urine EtG test reaches further, about 80 hours, or a little over three days. That works for short-term monitoring, but still leaves weeks uncovered if you're trying to document a pattern rather than a single incident.
PEth is a different category of test. Because it forms directly in your red blood cells after drinking, it stays detectable for roughly 2 to 4 weeks, and sometimes longer with heavy drinking. That's why courts, custody evaluations, and recovery programs ask for PEth specifically. They're not asking "did this person drink last night?" They're asking "has this person been drinking heavily over the past several weeks?" Only PEth can answer that.
Which one is right for you?
-
Checking the last few days? Choose the EtG Urine Test →
-
Need a result right now, for work or a checkpoint? Choose Breath Test →
Where Can I Get a PEth Test in Mesa?
Right here at Quick Test, on East University Drive at Power Road.
Walk in or book online Monday through Friday with your photo ID and any court or program paperwork if needed. The blood draw takes just a few minutes.
Serving: Mesa · Gilbert · Queen Creek · Apache Junction · San Tan Valley · Chandler · Tempe
What Do PEth Test Results Mean?
PEth results are reported as a number, in nanograms per milliliter (ng/mL).
Labs commonly use these ranges:
-
Below 20 ng/mL: abstinence or very light, occasional drinking. This is generally reported as negative
-
20 to 200 ng/mL: significant or moderate drinking
-
Above 200 ng/mL: heavy or chronic drinking
Levels well above 200, including 400 and higher, are commonly seen with heavy, frequent drinking.
Your court, probation officer, or program decides what level they act on, so share your full report with them.
Results also vary from person to person, which is why PEth is best read as a pattern over weeks, not a precise drink count.
Why Mesa Chooses Quick Test Health Services®
-
Walk in or book a set time online Monday through Friday,
-
Affordable, transparent pricing so you know the total before you pay
-
A quick, single blood draw, with most visits taking just a few minutes
-
Lab-documented results with chain-of-custody docuementation in about 3 to 5 business days, posted to your
Can Anything Throw Off a PEth Test?
False positives from everyday products are very unlikely.
Because PEth forms only from alcohol you actually drink, incidental exposure doesn't come close to a positive result. In one study, people used an alcohol-based mouthwash regularly, and none of them reached the 20 ng/mL cutoff.
Research has also shown that hand sanitizers don't affect PEth results.
What does affect results is timing and individual differences. People form and clear PEth at slightly different rates, so two people who drink the same amount can get somewhat different numbers. Results just above or below 20 ng/mL are the hardest to interpret, which is why PEth is often used alongside other tests, like EtG urine or EtG hair, when the stakes are high.
Frequently Asked Questions
Will 4 beers show up on a PEth test? It depends on how often. Four beers once, after weeks of not drinking, may stay under the cutoff. Four beers a day for several days is much more likely to show up, and can reach the heavy range.
How much does a PEth test cost? $165 total at Quick Test Health Services.
Does mouthwash or hand sanitizer affect a PEth test? No. Research shows normal use of alcohol-based mouthwash and hand sanitizer doesn't raise PEth to a positive level.