How Soon can Drugs be Detected in Urine?

Urine drug testing detects evidence of recent drug use or misuse in a sample of urine. Testing can detect illegal or prohibited drug use, prescription medications, over-the-counter medicines, and legal substances such as alcohol and tobacco.

Many factors affect the length of time a test can detect a certain drug in the body. These factors include:

• body mass
• hydration levels
• the acidity of the urine
• how long ago the person takes the drug

If a person uses a drug very frequently or heavily, a urine drug test will detect the drug for a longer period. This table shows how long a urine drug test can detect certain drugs after a person has taken them:

Drug	Drug Detection time after use
Alcohol	7–12 hours
Short-acting barbiturates	24 hours
Amphetamines	48 hours
Heroin	48 hours
Morphine	48–72 hours
Cocaine metabolites	2–4 days
Methadone	3 days
Short-acting benzodiazepines	3 days

While a urine drug test may only look for evidence of the use or misuse of one drug, tests are often combined into broad screening panels that test for several drugs at once, such as a 10-panel drug test. Positive results on an initial drug screening panel are considered presumptively positive and should be confirmed by an additional, more specific, confirmatory test.