Use of hand sanitizer can produce false-positive breathalyzer results

February 27, 2013, 9:17 pm


Common Hand Sanitizer May Distort Readings of Breathalyzer Tests in the Absence of Acute Intoxication. Ali SS et al. Acad Emerg Med 2013 Feb;20:212-215


The goal of this clever study was to determine if use of ethanol-based hand sanitizer by an operator administering a breathalyzer test affected results. Participants reported not consuming ethanol in the previous 24 hours, and had initial breathalyzer readings of zero on an Alco-Sensor III breathalyzer device. There were 3 study groups of 25 subjects each:

  • Group 1: Operator applied one pump (1.5 ml) Purell Hand Sanitizer (62% ethanol) to his/her hands and rubbed hands until dry.
  • Group 2: Operator applied one pump Purell and performed test before it dried.
  • Group 3: Operator applied two pumps (3.0 ml) Purell and performed test before it dried.

Results were as follows:

  • Group 1: breathalyzer results ranged from 0.000 to 0.016 g/dL.(median 0.004)
  • Group 2: breathalyzer results ranged from 0.020 to 0.109 g/dL (median 0.051)
  • Group 3: breathalyzer results ranged from 0.020 to 0.166 g/dL (median 0.119)

The authors conclude:

The use of an alcohol-based hand sanitizer can cause false-positive readings of a breathalyzer when the operator uses the hand sanitizer correctly. The breathalyzer readings are further elevated if more sanitizer is used or if it is not allowed to dry appropriately.

This is useful information. Although the results in Group 1 would not be clinically significant, some of the subjects in Group 2 and most in Group 3 had false-positive results above the legal limit.


  1. Amanda Says:

    Are there any studies controlling for blood assays? And how long dis they wait between “drying” and the test?

  2. Leon Says:


    Great questions!

    There have been multiple investigations of the effects of using hand sanitizers on blood alcohol levels. As pointed out in this paper:

    “Other previous studies have documented that these commonly available hand sanitizers do no significantly elevate the blood alcohol levels in individuals who have applied it to themselves.”

    In one study cited, subjects applied an ethanol-based hand sanitizer 50 times (!) over 4 hours. After this, blood alcohol level in each of the 5 subjects was less than 0.005 g/dL.

    Although this present study is not specific about an exact time interval, the authors say that the breathalyzer reading was determined “immediately” after application of the hand sanitizer, or for Group 1 immediately after the sanitizer had dried.

  3. Michael Says:

    If the blood levels of ethanol were high enough for some participants’ exhalations to produce a reading above the legal limit, how can the study authors suggest that the participants having those blood levels were not intoxicated?

  4. Ben Richardson Says:

    Unless I misread this, the operator is not the person who blew into the meter. Therefore this is not a test of alcohol entering the bloodstream through the dermis. This was a test of the alcohol present in the air around the test device and the false positives from this atmospheric contamination.

  5. Leon Says:


    You are correct. The operator of the test used the hand sanitizer, producing false positive results because of off-gassing of ethanol from his/her hands.


    I had the same question you did, until I re-read the paper two or three times and finally figured out the exact methodology. The authors certainly could have been clearer, especially in their title.

  6. Michael Says:

    Unfortunately, details become obscured as the information gets passed along. See for example,

    which posits a reason for the _subject_ rather than the _operator_ having higher blood levels!and then gets picked up by the Associated press and then Fox News, which added “But for people whose jobs require repeated hand sanitizer use—such as doctors and nurses—the amount of alcohol absorbed through the skin could lead to a false positive.”

    The story keeps getting changing a bit as it gets closer to Fox News

  7. Leon Says:


    Indeed, I have seen much confused commentary about this story. However, I believe the 2011 Gainesville Sun story you reference related to a different, earlier study that did not involve breathalyzers but looked for specific biomarkers in the urine of subjects who used hand sanitizers.