Testing people for previous drug use
Urine testsMDMA can be detected in urine tests for 2 to 5 days after use. This depends mainly on the size of the last dose taken, as every six hours the amount in your body is halved. So a 128 mg dose taken at midnight would reduce to 64 mg by 6am; 32 mg by midday and so on down to 1 mg in less than 48 hours. However, if you take several Es every weekend, it is possible that some may be stored in your body fat and will be released gradually over a couple of weeks. Remember too that other drugs, especially amphetamines, respond to the same tests.
The easiest drug to detect is cannabis which is stored in body fat and slowly released. It can be detected up to "five weeks after a single reefer" according to Dr Henry of the National Poisons Unit, although people who drink plenty of water may not be detected after two weeks. LSD is hard to detect even after a few hours. Mushrooms are also hard to detect.
There are many rumours about how to pass the piss test, but the best way is to wash yourself out and dilute your urine by drinking lots of water right up to the test. Vitamin C will help get rid of most drugs, and is probably as effective as the highly priced products sold for the purpose.
Hair testsDrugs in the bloodstream are deposited in hair as it grows, so a length of hair can provide a record of your drug use while it was growing. This test is expensive and not completely reliable at present, but may become so. A company in Scotland has advertised to test samples of children's hair sent in by parents to see if they use drugs.
Swab testsAn American company called Barringer is marketing DrugAlert which they describe as "a low cost weapon in the war against illegal drugs". This costs about $35 or £20 and consists of a swab to wipe surfaces (such as the telephone) touched by someone suspected of using drugs, which is then returned and analysed. Their results cannot be used in a court of law as the samples is destroyed while testing. Their phone number is +1 908 665 8200.
They claim to be able to detect amounts as small as a nanogram (a billionth of a gram) of cocaine, heroin, methamphetamine, LSD, PCP, marijuana and amphetamine derivatives including ecstasy.
The problem with such sensitive tests is that they may show positive due to indirect contamination.