Originally Posted by
peekay4
Since these machines are detecting ethanol specifically, they are extremely accurate. False positives are rare. Due to their accuracy these machines are typically acceptable in a court of law in lieu of a blood test.
A disease which could produce ethanol in detectable levels is also extremely rare (known as auto-brewery syndrome). Most of us may produce a trace amount of ethanol in our guts, yet in the entire history of humankind there are less than 100 recorded cases of auto-brewery syndrome. If you are unlucky enough to suffer from this disease, you may lose your flight medical anyway because you are essentially drunk all the time.
To lend support to the above, member of my family has a PhD in this field and regularly consults with CASA (Australia's Civil Aviation Safety Authority) and the Commonwealth Dept of Transport and has authored several reports on this topic.
I asked him his view on false readings and screening in general. His reply just now:
"Drug and alcohol testing programs should be conducted on a regular basis across all of the aviation industry. There can be no doubt to the adverse effects on say a pilots performance when impaired by alcohol, drugs or fatigue. Though there is still frequent disagreement over who is classified safety-sensitive personnel, or whether testing should be a mandatory part of a company's safety mangement system - especially given the costs involved - the industry is continuing to make positive strides.
From my experience, false-positive test results are extremely rare - I've only seen one - given the sensitivity and nature of the equipment employed today. If you are working in a safety-sensitive position and your performance is impaired, the responsibility and consequences from any possible adverse effects is on you. Period."
Harsh, but I understand where he's coming from.
As an aside, he's mentioned on numerous occasions that he's becoming increasingly alarmed by the number of incidents where fatigue is a causal factor.