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This Article Was Originally Published in the Respected Scientific Journal "New Scientist" Date noted below:


Magazine section: This Week - Focus

The prying game

New Scientist vol 163 issue 2196 - 24 July 1999, page 18


Drugs tests in the workplace are increasing on both sides of the Atlantic. But researchers are questioning their relevance . . . and worse, their reliability


LSD turns up in a woman's urine sample. If this was one of the increasingly common workplace drugs tests, she'd probably be out of job. But the woman is an 82-year-old intensive care patient who had never taken LSD in her life. The only fun she had was taking ambroxol, an over-the-counter medicine, which in addition to clearing mucus from her lungs, caused the bogus test result.

Drugs tests are supposed to be a fast and accurate way for employers to spot workers who are indulging in illicit thrills. But mounting evidence suggests otherwise. Last year, after "finding LSD" in the 82-year-old woman's urine by serendipity, the same German researchers uncovered 11 other false positives for the drug following urine tests of a kind widely used in German drugs screening labs.

This is disturbing, since drug testing is a growth industry. According to Lewis Maltby, director of the American Civil Liberties Union's workplace rights office, 80 per cent of large US companies now test their employees. Britain and Europe are catching on. The British government's Forensic Science Service is coy about the number of UK companies paying for its drug-testing service, but a spokeswoman said that "demand is growing all the time". Last month, the Police Superintendents' Association of England and Wales called for the law to be changed so that random drugs tests can be carried out on all police officers. Existing British laws such as The Transport and Works Act of 1992 require some employers, such as providers of public transport, to ensure their staff are drug-free on the job. As a result these organisations perform random testing on employees—although less extensively than counterparts in the US. However, doubts about the validity of such tests remain.

Apart from the question marks over reliability, it is unclear whether companies are harmed by drug use or even whether testing employees actually helps business.

The most recent survey from the US National Institute on Drug Abuse (NIDA) estimated that drug misuse by employees cost the country $14.2 billion in lost productivity in 1992, and their employers had to pay twice as much in medical and compensation claims as for their drug-free colleagues. But last year, researchers from Le Moyne College's Institute of Industrial Relations in Syracuse, New York state, examined the productivity of 63 high-tech firms and found that companies testing workers were less productive than firms which trusted their staff to be "clean". The reasons are unclear, but testing is time-consuming and expensive, and can undermine the morale and loyalty of staff. And some workers may even use drugs to boost their performance, the researchers say.

Private lives

Civil rights groups are quick to point out that the tests may identify substances at insignificant doses because of recreational drug use outside working hours and that such activity has no bearing on their performance as employees.

Owen Tudor, policy officer of the British Trades Union Congress says: "We're very concerned there is a creeping intrusion into people's private lives." Such fears haven't deterred American society from embracing the drugs testing culture, and tying itself in some legal knots in the process. For example, in 1997, the Supreme Court ruled that a Georgia law requiring political candidates to be drug tested violated the Fourth Amendment's prohibition against unreasonable searches. But in March last year, the same court upheld the legality of compulsory random drugs tests for White House employees, presumably to ensure the President is not served by drug-addled interns or worse, senior advisers under the influence of narcotics.

But it's important to recognise the distinction between tests applied to public workers and the tests carried out by private companies, says Marilyn Huestis, acting chief of NIDA's drug metabolism programs. Federal employees working in sensitive departments, the military, and those covered by transport regulations routinely have their urine tested for five key drugs—marijuana, cocaine, opiates, amphetamines (including "speed") and PCP, the hallucinogen known as "angel dust". Seventy-odd labs certified by the Substance Abuse Mental Health Services Administration (SAMHSA), which has responsibility for federal testing standards, perform the tests on samples kept under strictly controlled conditions. Samples that come up positive are double checked by a gas chromatograph mass spectrometer, the "gold standard" test that identifies a substance's exact molecular structure. A doctor then reviews the findings.

In contrast, some private employers work to lower standards. While some do follow SAMHSA procedures and use federal laboratories, others use poorly trained staff and commercial drugs testing kits to perform on-site tests that are never confirmed, says Huestis. "You go from one extreme to the other," she says. It all depends on the company and the laws of the particular state. In the UK, the respected Forensic Science Service does much of the testing for private companies. But a number of smaller private testing services are also vying for business.

Earlier this year, Howard Taylor, director of laboratory services at the US National Safety Alliance, a firm which runs drugs testing programs for over 5000 companies, tested five commonly used commercial kits for testing urine samples on site. All the manufacturers claimed their tests were as accurate as any done in a lab. But that's not what Taylor found. "The results indicated discrepancies between claims and performance for all products," he says.

Four out of five kits recorded positives for tetrahydrocannabinol (THC), the active ingredient in marijuana, at levels 25 per cent below the SAMHSA's cut-off. Three kits recorded positives for morphine and two kits registered PCP below similar cut-off levels (Journal of Analytical Toxicology, vol 23, p 119).

Some employers may regard the SAMHSA cut-off levels to be as redundant as workers with even the minutest amounts of an illegal drug in their system. But what if someone tests positive without taking any illegal substances?

It can happen—just by eating lunch. In 1997, Judith Bonicamp and Ida Santana, chemists at Middle Tennessee State University, Murfreesboro, showed that poppy seed dressings contain enough opiates to make you test positive for morphine (Microchemical Journal, vol 58, p 73).

Sex is a more bizarre reason for failing a cocaine test. NIDA studies have shown cocaine can be passed on in semen and absorbed through the vagina, although the amounts are too small to register in most tests. However, if drugs such as cocaine are placed on the lips or other areas of the body, the risk is higher. It's quite likely that enough could be transferred to another person through kissing or other oral contact to produce a positive drugs test, says Dan Berkable, president of the American Toxicology Institute in Las Vegas.

The problems associated with urine testing have sparked interest in alternative techniques, mainly hair, sweat and saliva testing, says Huestis. Proponents of hair testing argue that it is less invasive and offers a much larger window of detection, as drugs stay in hair long after they have been metabolised by the body.

But hair testing is controversial too, mainly because natural hair colour can affect the amount of drug detected. Edward Cone, now retired from NIDA, found that significantly more cocaine binds to the very dark hair of male Afro-Americans than to hair of other groups.

SAMHSA's Drug Testing Advisory Board is looking at whether hair, sweat or saliva tests could be appropriate for federal test programs. Each may prove to be faster, cheaper and more sensitive than current methods. But they come with their own problems, and the Board is trying to draw up stringent guidelines to govern their use.

Regardless of the tests used, civil rights groups remain concerned. "Of course we want employees to come to work sober," says Maltby of the American Civil Liberties Union. "But private companies that indiscriminately test are inevitably going to fire innocent people."


Matt Walker