Tests that claim to show weather or not a young person has been using drugs are a tempting option for family members concerned about a persons behaviour. But are drug tests everything they are cracked up to be?


Drug tests detect whether someone is under the influence of alcohol or whether they have taken drugs recently. The most common types of drug tests are urine drug screens (UDS), roadside saliva tests or breathe tests for alcohol. Other tests such as sweat and hair tests are not commonly used in Australia.

Urine drug screens are available through pathology centres and home testing kits are also sometimes used. 


It is a myth that there is one test that looks for all drugs in a persons urine. Drug tests where a doctor sends the urine sample away to a laboratory to be processed can test for common drugs (such as heroin, amphetamines and cannabis) and for chemicals that drugs break down into once it is in the body.

A lab will not routinely test for less common or emerging drugs unless requested.  Specialist machinery is required to pick up synthetic cannabis for example.

Home tests that can be purchased at chemists use much more basic technology and are therefore less accurate. Even if a home test does come up as positive, there is no way of knowing weather drugs have actually been used or the test has been influenced by other factors and is showing a ‘false positive.’


A young person may undertake drug testing for numerous reasons. These include:

  • As a legal obligation to comply with an order or direction,
  • As part of an intake process for a treatment program (to assess risk of withdrawal and appropriateness for a program),
  • Voluntarily, when a young person has goals to cease or reduce drug use but does not have confidence managing this without external incentives or controls,
  • Voluntarily to “prove” to courts, families or friends that they are not using drugs or alcohol.
It is a myth that there is one test that looks for all drugs in a persons urine.


It is important to consider the following:

  • Drug tests, especially home tests are not 100% reliable,
  • There are many reasons why drug tests can produce false negatives or false positives. For instance levels of hydration and other medications can influence test results,
  • Drug tests don’t always detect every illicit drug,
  • Different drugs stay in the body for different lengths of time and are broken down at different rates. This means tests for some drugs may come back positive even a young person has not used for quite some time or since a previous drug test. 
  • Drug tests don’t take the place of open and honest conversations.

If you are considering drug testing a young person you care about we also recommend reading our article that explores this more.