This page covers different types of drug tests, how they are carried out and some of the things that might affect their results.
A drug test is a test to find out if you have used a drug. Drug tests look for very small amounts of drugs in the body. There are different types of drug tests, including breath, blood, hair, saliva and urine, which test for various drugs.
Drug tests can't tell exactly how much of a drug was used or exactly when it was used.
Breath drug tests are convenient and inexpensive and are often used to detect alcohol.
If you are asked to have a breath test, you will be asked to blow into a hand-held device until you breathe out air from deep within your lungs. From this, your blood alcohol content (BAC) will show up on a digital display on the testing device (called a breathalyser). Breathalysers are used to estimate BAC rather than blood or urine tests because they are accurate, inexpensive and easier to conduct. Random roadside breath testing for alcohol happens in all Australian states and territories.
Blood drug tests are used to test for very recent drug use, ie. within a couple hours of use. However, blood tests are not used very often because they are expensive.
If you are asked to have a blood test, a sample of your blood will be taken from a finger prick, or from a vein in your arm, using a needle. Your blood sample will be tested by an accredited laboratory.
Hair drug tests are currently the only tests that can reliably detect drug use beyond a couple of days or weeks. However, hair tests are not used very often because they are expensive.
If you are asked to have a hair drug test, approximately 40–50 strands of your hair will be cut from the scalp line at the crown of your head. A laboratory will test your hair sample for drug use. Most hair drug tests don't detect drug use further back than the past 3 months.
Saliva drug tests are becoming more common. They are often used by employers in the workplace and by the police in random roadside drug testing. Saliva tests are usually quick, accurate and reliable. Saliva tests are especially good at detecting THC (delta-9 tetrahydrocannabinol, the active part of cannabis) and amphetamines ('speed').
If you are asked to have a saliva test, you will be asked to put an absorbent collector in your mouth or on your tongue, to get a sample of your saliva.
If you are asked to have a random roadside drug test, the police will test your saliva at the roadside. This will take about 5 minutes. If the result of the test is positive, you will be taken to a drug bus and asked to give a second saliva sample. If this sample also tests positive, it will be sent to a laboratory for more testing. Random roadside drug testing happens in all Australian states and territories.
Urine drug tests can detect drug use further back in time than blood tests (but not as far back as hair tests). Urine drug tests are often used in workplaces, and usually give accurate results.
If you are asked to have a urine test, you will be asked to urinate (pee) into a container. Your urine will be tested using a dipstick. If the test is positive your urine sample will be sent to a laboratory for more testing.
Drugs affect people differently, and are metabolised (processed) by people differently. Results of drug tests are always unique to the person who was tested. This means that you and a friend could take the same amount of a drug, at the same time, and have the same type of drug test, but have different test results. This is because individual things about you and your drug use can affect the results.
Other than not taking drugs, the only sure way to pass a drug test (i.e. to test negative) is to make sure your body has metabolised (processed) all of the drug(s) you have taken.
Getting a negative drug test result (ie. passing) means:
There are myths that taking various substances (e.g. aspirin, niacin, bleach, vinegar, cranberry juice, goldenseal) will mask or disguise drug use in tests and give you a negative test result. There are also products sold that claim they can help you pass a drug test. However, there's no reliable evidence that any of these actually work.
There's no guaranteed way to get rid of a drug other than waiting for your body to metabolise it. If you know you will be drug tested and you are worried, don't use drugs.
Drinking lots of water does not work to cheat a urine (or a blood) drug test. Most urine tests check for dilution (too much water) and may reject your results because of this.
Also, you can actually get sick from drinking more water than your body can handle. This is called "water intoxication" or "water overdose". If you drink too much water, your kidneys can't get rid of it quickly enough. This can cause headaches, blurred vision, cramps and eventually convulsions.
If you have taken more than one drug at a time (including alcohol), your body may take longer to metabolise them than if you had only taken one. Most drugs will stay in your body for at least 24–48 hours, so they don't need to be taken at exactly the same time to have an effect on each other.
Remember that even if you don't feel the effects of the drugs anymore (e.g. you don't feel stoned), they can still be in your body.
A false positive is a test result that is positive for a drug that you haven't taken. It is false because the result is incorrect. A false positive usually means that the test wasn't sensitive enough to be able to tell the difference between two drugs.
Traces of cannabis could be found in your body fluids if you have inhaled someone else's cannabis smoke (called passive cannabis smoking). However, testing companies usually say that the concentrations of these traces would be too low to give a positive test result for cannabis.
Cannabis is stored in the body differently to other drugs. If you use cannabis once, the body can get rid of it fairly quickly (within a couple of hours). However if you are a regular user of cannabis, the THC (the active ingredient in cannabis) accumulates in your body's fat cells and can take a long time to be broken down and metabolised. THC can be detected by a urine test for up to 6 weeks after regular use.
Drug testing kits can be bought online and from some pharmacies. There are different types of kits, which test a range of drugs. These kits are often promoted to parents as a way of finding out if their kids have used drugs.
The reliability and quality of these testing kits has improved greatly over the last few years but most of the kits are still limited, for example they can only detect use of common illicit drugs like cannabis and amphetamines, and not new psychoactive substances like synthetic cannabis and mephedrone.
There can also be issues with actually doing the tests. For example, if a parent wanted to test their kid, who didn't want to be tested and denied taking drugs, their relationship could be seriously affected.
There are also kits available for sale that are designed to test for the presence of drugs such as MDMA (ecstasy) in pills. There has only been only a small amount of research into how accurate and reliable these tests are. Many of these testing kits are limited because they can't tell the difference between drugs like MDMA and the other substances often included in ecstasy pills like PMA or PMMA. However, the kits can give some valuable information about the content of pills by detecting the presence or absence of ecstasy-like substances.
At some point in your life you may be asked to have a drug test.
Australian public schools don't drug test their students. However, drug testing of students in private and boarding schools may be part of the school's drug policy. If you are a student in one of these schools, you could be asked to have a drug test.
Drug testing in workplaces is usually used when there are safety issues related to the job, such as driving a vehicle or operating machinery. If you are employed in this type of work, you could be asked to have a drug test as a requirement of the job. There will probably be consequences if you refuse, such as losing your job.
If you are driving, anywhere in Australia, and refuse a random roadside breath or drug test when you are asked to have one, you can be fined or lose your licence.
Information in this page is meant as a general guide only. While we (the Australian Drug Foundation) have worked hard to make sure that the information on this page is complete and correct, we do not claim that it is perfectly complete, accurate, reliable or suitable. We do not offer any information in this fact sheet as a tool for treatment or counselling. We recommend that before making any decision based on any information on this page, you should seek independent professional advice.
|Last Updated ( Wednesday, 19 February 2014 10:50 )|