A toxicology test ("tox screen") checks for drugs or other chemicals in your blood, urine, or saliva. Drugs can be swallowed, inhaled, injected, or absorbed through the skin or a mucous membrane. In rare cases, a tox screen may check your stomach contents or sweat.
A tox screen may check for one certain drug or for up to 30 different drugs at once. These may include prescription medicines, nonprescription medicines (such as aspirin), vitamins, supplements, alcohol, and illegal drugs, such as cocaine and heroin.
Testing is often done on urine or saliva instead of blood. Many drugs will show up in a urine or saliva sample. And urine and saliva tests are usually easier to do than blood tests.
Why It Is Done
This test may be done to:
- Find out if a drug overdose may be causing life-threatening symptoms, unconsciousness, or strange behavior. It is usually done within 4 days after a drug may have been taken.
- Check for drug use in the workplace. Testing is common for people who work in public safety, such as bus drivers or child care workers. Some jobs require a tox screen as part of the hiring process.
- Check for drug use in students involved in extracurricular activities, such as sports and cheerleading.
- Look for the use of drugs that enhance athletic ability.
- Check for the presence of a date rape drug.
How To Prepare
Many medicines can change the results of this test. So give your doctor a list of all the medicines you have taken in the past 4 days. Be sure to include any prescription and over-the-counter medicines, vitamins, and natural health products.
You will be asked to sign a consent form that says you understand the risks of the test and agree to have it done. If you are a student, your parents may also need to sign a consent form before you can be tested.
Talk to your doctor if you have any concerns about the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).