The presence of various classes of abused drugs can be tested for. This usually consists of an initial screen where the drug group (e.g. opiates) is detected; positive results are then followed up by a more specific test which identifies the individual drug taken (e.g. morphine).

A drugs of abuse ‘screen’ usually covers the most commonly abused drug classes which are the opiates, benzodiazepines, barbiturates, cannabinoids, amphetamines (including ecstasy) and cocaine. Drugs used in the treatment of opiate addiction (methadone and buprenorphine) are also often searched for.