A toxicology test checks blood, urine, or saliva for
the presence of drugs or chemicals. In rare cases, stomach contents or sweat may
also be checked.
Drugs can be accidentally or deliberately
swallowed, inhaled, injected, or absorbed through a skin surface or
mucous membrane. These include prescription medicines,
nonprescription medicine (such as aspirin or acetaminophen), vitamins,
nutritional supplements, alcohol, and illegal drugs, such as cocaine and
A toxicology test may check for one specific drug or for
up to 30 different drugs at once. Testing is often done on a urine or saliva sample
instead of blood, because urine and saliva tests are usually easier to do than blood tests
and many drugs show up in either urine or saliva. Traces of a drug may remain in urine longer than in blood. Urine tests often can detect drug use within the last 5 days. Saliva testing can detect drugs used within the past day.
Why It Is Done
A toxicology test ("tox screen") can be
- Help find the cause of life-threatening
symptoms, unconsciousness, or bizarre behavior in an emergency situation. It is
usually done within 96 hours (4 days) after a drug may have been taken. The
toxicology test is used to find out if symptoms may be caused by a drug
overdose. Both a urine sample and a blood sample may be
- Test for drug use in the workplace, especially for people
who are involved with public safety, such as bus drivers or child care workers.
A toxicology test may also be a normal part of the application procedure for
some jobs. This may be done on either a blood or urine sample.
- Test for drug use among middle school and high school students involved in competitive extracurricular activities. Such activities include athletics, cheerleading, choir, band, and foreign language clubs.
athletes for the use of drugs that enhance their athletic ability. This is
usually done on a urine or saliva sample.
- Evaluate the possible use of date
rape drugs. This is usually done on a urine sample.
How To Prepare
Many medicines may change the results
of this test. Be sure to tell your doctor about all the nonprescription and
prescription medicines you take. Make a list of any medicines (prescription and
nonprescription), herbal supplements, vitamins, and other substances you are
taking or have taken in the past 4 days.
You will need to sign a
consent form that says you understand the risks of the toxicology testing and
agree to have it done. If you are a student involved in competitive extracurricular activities, your parents may also need to sign a consent form before you can be tested.
Talk to your doctor about any concerns you have
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
medical test information form(What is a PDF document?).