Drug testing at work

You don't have to resign in a blind panic, but you do need to know where you stand.

You are what you wee

Your body attempts to break down anything you shove inside it, from food to drink and drugs. 'Metabolites' are formed as part of this process, and testing looks for specific types that could only occur as a result of drug taking and can remain inside the body for long periods.

High times? Testing times

If a tester had to nominate the most easily-detectable drug, it would probably be cannabis. The active ingredient in cannabis is called THC, and the metabolites from THC can take weeks to clear the body, depending on your body size and drug habit. As a non water-soluble substance, you can't flush THC from your system overnight. Instead, it tends to get caught up in the body and released at a much slower rate. Smoking a joint a couple of nights a week may take 21-28 days to clear the system. Heavy cannabis use may be detected in the system up to 42-56 days later.

Here's a rough guide to some other drug metabolites that outstay their welcome, and which a urine test won't miss:

• 2-4 days: Amphetamines, cocaine, ecstasy, heroin and other opiates.
• 1-7 days: Barbiturates.

Other tests

Drug metabolites can be also be detected in blood, perspiration and other body residue, but hair is an increasingly popular testing ground. Why? Because metabolites can supposedly filter out with hair growth and resist pretty much everything from shampooing to perm jobs. Testing involves dissolving the hair sample in a series of solvents that extract the drug metabolites.

Can it be dodged?

Short of shaving your head, or having a ready supply of infant wee to hand, there is no sure-fire means. There are many products on the market that claim to beat the test, mostly by adding masking substances to your urine sample. However, the means of detection is becoming increasingly sophisticated, so what might work one day might fail badly the next.

The legal position for drug testing is complicated. It's acknowledged that employers have a justifiable interest in employees' drug use in certain circumstances. These include employees using drugs or alcohol in the workplace, or if drug or alcohol use is affecting your performance or safety at work. But the principles behind current measures also state that people are entitled to a private life and dignity. A drug test shouldn't be imposed on you, and should only be introduced after a consultation and in good faith.

But I'm innocent!

There's lots of debate over the accuracy of drug test results. If you really haven't taken drugs and your test comes back positive, it's time to have a serious talk with your boss, and if they're not listening, get some legal support.

Testing positive for drugs doesn't automatically mean dismissal. Your employer may decide to shift you to another part of the company if safety is an issue. They may even offer you help and support, especially if you're more than a recreational user. The best ammunition against a positive result is to be a star employee that they just can't live without!