Teenage drinkers face alcohol test
- 14 February 2007
- Andy Coghlan
Big Brother has arrived at a high school in New Jersey. Determined to stop their students consuming alcohol at weekends, staff at Pequannock Township High School in Morris county are to start using a controversial test that can detect if students have been drinking up to a week earlier.
The test measures urine concentrations of an ethanol breakdown product called ethyl glucuronide (EtG). "We plan to use this new test as part of our comprehensive testing programme to keep our kids safe from the dangers of drugs and alcohol," says Larrie Reynolds, superintendent of Pequannock High School. "About four to eight kids will be tested every day." In New Jersey drinking alcohol is illegal under the age of 21.
Drinking is a growing problem in US schools. "As many as half of our kids are doing this," says Reynolds. An estimated 1700 US high-school students died from alcohol poisoning or related accidents in 2005 alone.
However, the EtG test poses a problem. It is so sensitive that even total abstainers can sometimes test positive. Alcohol absorbed from soaps, mouthwashes or contaminated vinegars or by drinking a sip of communion wine can be enough.
The EtG test poses a problem. It is so sensitive that even total abstainers can sometimes test positive”
Despite this, the test's popularity is growing, and around a dozen commercial versions are now available. Estimates by the US Department of Health and Human Services (DHHS) suggest that as many as 20,000 tests are being performed each month, mainly among medical staff - including 9000 physicians - pledged to abstinence following the discovery that they have a drink problem. Law firms and the military have started using it on their staff too. Greg Skipper, medical director of the Alabama Physician Health Program, says the test has been invaluable for monitoring doctors in recovery from alcoholism. "It enables them to comply, stay sober and keep their jobs," he says.
Skipper is, however, critical of health boards and agencies in some states that he says have been automatically sacking people who fail the EtG test without using other tests to confirm its findings. In the three to four years that the test has been commercially available in the US, more than 100 nurses in recovery from alcoholism have complained of losing their jobs after testing positive despite, they say, not drinking. Blood tests for a second metabolite such as phosphatidyl ethanol would be far less likely to give a false positive, as this substance appears only after large amounts of alcohol have been consumed, but these tests are more expensive.
In 2006, Skipper helped compile an advisory document for the DHHS which stated that "legal or disciplinary action based solely on a positive EtG test is inappropriate". Since the advisory was published, Skipper says there has been a fall in the number of complaints of unfair dismissal posted on a website he set up (http://www.ethylglucuronide.com/).
Using the EtG test alone, the risk of false positives remains, particularly in hospital wards, where nurses and doctors routinely use soaps containing ethanol. "In intensive care units, nurses and doctors apply it every 5 minutes," Skipper says. He has shown that the test could give a positive result in ward staff who have simply breathed vapour in. Even bystanders can test positive.
Both Skipper and the test's creator, Friedrich Wurst of the psychiatric clinic at the University of Basel, Switzerland, say that there is not yet an agreed threshold concentration that can be used to separate people who have been drinking from those exposed to alcohol from other sources. Below 1000 nanograms of EtG per millilitre of urine is probably "innocent", and above 5000 booze is almost certainly to blame. In between there is a "question zone", Skipper says.
Skipper backs use of the tests by schools if they accept its limitations. "Schools must have a system for dealing with positives, managed by a medical review officer, and not automatically expel the child," he says.
From issue 2591 of New Scientist magazine, 14 February 2007, page 14
Contributor: Don Phillips