PEth Testing Dried Blood Spots

Dried blood spot collection is the fastest, most convenient way to test for phosphatidylethanol (PEth). Phosphatidylethanol (PEth) is created in red blood cells where it exists as part of the cell membrane. Research suggests a PEth test can differentiate between incidental exposure (hand sanitizer use, etc.) and the intentional use of ethanol. 

PEth is an abnormal phospholipid formed in red blood cells following alcohol exposure. PEth in blood exists as a component of the red cell membrane. PEth is stored in the cell membrane and can be extracted from dried blood spot specimens and measured to identify alcohol exposure.

PEth is a mid to long-term alcohol biomarker, and a positive result (measuring phosphatidylethanol species 16:0/18:1) is an indication of alcohol exposure during the 2-3 weeks prior to sample collection.

The sample amount is 5 dried blood spots from a finger puncture or 5 ml of blood from a standard blood draw using anticoagulation tube collection.


Unlike venipuncture, dried blood spot collection is performed by the individual being tested (the donor) and can be observed by any staff member, after a short training session. The dried blood spot drying box makes collection even easier by eliminating wait time.

Advantages of PEth

  • 100% specific for ethanol. PEth can only be formed in the presence of ethanol.
  • Identifies heavy episodic drinking (5 or more drinks in one sitting) for up to the last 30 days prior to measurement.
  • PEth levels are not affected by race, gender, BMI, or disease state.
  • Dried blood spot specimens for PEth analysis are easy to collect and non-invasive.