A 3 month analyis of hair was taken for evidence to show whether I have consumed any alcohol over this period, I have not but the result has come back at a reading of 0.039, what could have caused this detection.

You are drinking mouthwash or something with a high alcohol content or someone is sneaking alcohol into your body when you are asleep.

Ask for a second test.

I know in our breath tests we would do three separate readings and each had to be within a certain level of the others to make one valid test.

This figure has nothing to do with alcohol content. Alcohol is not absorbed into the hair. Only it's metabolites.

The figure you provided is in all likelihood 0.039 ng/mg and a measurement of Fatty Acid Ethyl Esters (FAEE) Placing reliance on information provided by Tri-Mega Labs (London) (http://www.trimegalabs.co.uk/tests/hair-alcohol-testing-science.php), total abstainers can be expected to register between .15 - .45 ng/mg. This laboratory, the first to do hair testing for alcohol, standardly uses a cut-off of 1.0 ng/mg. [The lowest cut-off I've found was 0.5] Therefore, if a measurement of FAEE in the hair (most likely) you are well within the expected range for people who consume no alcohol. This occurs from incidental exposure to environmental sources of ethanol.

The only other possibility is that it is a measurement of ethylglucuronide (EtG), another metabolite of alcohol, that can also make it's way into the hair. I find that doubtful as Greg Skipper, MD, (June, 2009) (http://etg.weebly.com/etgets-blog.html) who introduced EtG testing in the US, believes that use of the technology for alcohol detection in hair samples is unreliable and discourages such use.

Your question surprised me as last I checked there was only one lab in the US doing alcohol hair testing, in Chicago I believe. While hair testing was common for other drugs it wasn't widely used at all for alcohol prior to 2008 although Tri-Mega had been using it in Europe for a couple of years. It's an expensive technology.

I would appreciate knowing what laboratory performed the test.