A toxicology test checks blood or urine for the presence of drugs. In rare cases, stomach contents, sweat, or saliva 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 heroin.
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 sample instead of blood, because urine tests are usually easier to do than blood tests and many drugs show up in the urine. Also, traces of a drug may remain in urine for longer than in blood.
