Urine drug screen

Alternative names
Drug screen - urine

Definition
A urine drug screen is designed to detect illegal drugs in the urine. See toxicology screen for information about specific drugs.

How the test is performed
It is necessary to collect a “clean-catch” (midstream) urine sample. To obtain a clean-catch sample, men or boys should wipe clean the head of the penis. Women or girls need to wash the area between the lips of the vagina with soapy water and rinse well. As you start to urinate, allow a small amount to fall into the toilet bowl (this clears the urethra of contaminants). Then, in a clean container, catch about 1 to 2 ounces of urine and remove the container from the urine stream. Give the container to the health care provider or assistant.

You may be asked to remove all your personal belongings and wear a hospital gown, then placed in a room where you have no access to your personal items or water. In this environment, you cannot dilute the sample, nor can you use someone else’s urine for the test.

The sample is then taken to the laboratory for evaluation.

How to prepare for the test
No preparation is necessary for this test.

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 in your urine, which indicates your recent ingestion of the drug.

Normal Values
No drugs in the urine.

What abnormal results mean
If the test result is positive, it is helpful to confirm the results with gas-chromatography mass spectrometry (GC-MS). In some case, a test will register a false positive. This can result from interfering factors such as some foods, prescription medications and other drugs. The GC-MS will help to eliminate some of the other possibilities.

What the risks are
There are no risks associated with this test.

Special considerations

There are no special considerations for this test.

Johns Hopkins patient information

Last revised: December 2, 2012
by Arthur A. Poghosian, M.D.

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