Urine Drug Screen: MedlinePlus Medical Encyclopedia

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You Are Here: Home → Medical Encyclopedia → Urine drug screen URL of this page: //medlineplus.gov/ency/article/003364.htm Urine drug screen

A urine drug screen is used to detect illegal drugs and some prescription medicines in the urine.

How the Test is Performed

Before the test, you may be asked to remove your clothes and wear a hospital gown. You may then be placed in a room where you have no access to your personal items or water. This is so you cannot dilute the sample, or use someone else's urine for the test.

This test involves collecting a "clean-catch" (midstream) urine sample:

• Wash your hands with soap and water. Dry your hands with a clean towel.
• Men and boys should wipe the head of the penis with a moist cloth or disposable towelette. Before cleaning, gently pull back (retract) the foreskin, if you have one.
• Women and girls need to wash the area between the lips of the vagina with soapy water and rinse well. Or, if instructed, use a disposable towelette to wipe the genital area.
• As you start to urinate, allow a small amount to fall into the toilet bowl. This clears the urethra of contaminants.
• Then, in the container you are given, catch about 1 to 2 ounces (30 to 60 milliliters) of urine. Remove the container from the urine stream.
• Give the container to the health care provider or assistant.
• Wash your hands again with soap and water.

The sample is then taken to the lab for evaluation.

How the Test will Feel

The test involves only normal urination.

Why the Test is Performed

The test is performed to detect the presence of illegal drugs and some prescription medicines in your urine. Their presence may indicate that you recently used these substances. Some drugs may remain in your system for several weeks, so the drug test needs to be interpreted carefully.

Normal Results

No drugs in the urine, unless you are taking medicines prescribed by your provider.

What Abnormal Results Mean

If the test result is positive, another test called gas-chromatography mass spectrometry (GC-MS) may be done to confirm the results. The GC-MS will help tell the difference between a false positive and a true positive.

In some cases, a positive test will be a false positive. This can result from interfering factors such as some foods, prescription medicines, and other drugs. Your provider will be aware of this possibility.

Alternative Names

Drug screen - urine

Images

• Urine sample

References

Bluth MH, Pincus MR, Abraham NZ. Toxicology and therapeutic drug monitoring. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 24.

Breuner CC. Substance use disorder. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 157.

Meehan TJ. Care of the poisoned patient. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 135.

Minns AB, Clark RF. Substance abuse. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 187.

Nelson LS, Calello DP. Acute poisoning. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 96.

Review Date 1/8/2025

Updated by: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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Related MedlinePlus Health Topics

• Drug Use and Addiction
• Urine and Urination