As drug testing becomes increasingly common, we look at what the tests can pick up.
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 which 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 up to 45 days 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.
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
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. Many people think these tests could be unreliable.
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.
But I'm innocent!
Drug testing is effectively in its infancy. At present, it is believed that more than 250 over-the-counter medicines, and some food ingredients, could cause a false positive result. So expect many legal disputes as the practice becomes more widespread in the workplace.
The charity Release gives advice on drugs and legal problems - their helpline number is 020 7749 4034.