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Other causes of failed PEth test for alcohol abuse?
Mental Health | Last Active: 3 days ago | Replies (430)Comment receiving replies
Fair enough @fairlaneowner, I just wasn't sure if the red blood cells in the sample would react with the alcohol from the swab and create the PEth byproduct outside the body. Just a thought. I attached some information from the Substance Abuse and Mental Health Services Admin that has some interesting information on biomarkers including PEth test.
I still am waiting for my appointment with my provider who ordered the PEth test. The information in the SAMHSA brochure, which was directly referenced on my lab report, states that a single biomarker should not be damming and taken into context with other tests for a solid picture. This literature even says false positives are "unlikely but still unknown due to paucity of research".
Replies to "Fair enough @fairlaneowner, I just wasn't sure if the red blood cells in the sample would..."
The RBC in the sample (in vitro) can absolutely continue to produce PEth. The PDL2 enzyme remains active until essentially frozen -80c
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Nope, but any sugar in the blood can ferment, and that can react with any PLD in the blood, and viola, PeTH. There are lots of research papers where they mention getting inconsistent results from folks who were currently intoxicated at the time of the test due to actual alcohol still being in the blood. They mention using a PLD inhibitor to stabilize the readings.
That's also why it's very important to allow the blood to dry before sealing it up for a DBS (dried blood spot) collection method to stop any enzymatic activity.
In whole blood they also mention freezing it right away to prevent enzymatic activity.