Urine Test

This procedure requires a fresh sample of urine, which may either be tested on-site or sent to a laboratory for testing. The sample should be sent for laboratory confirmation if the on-site test is positive. The lab typically performs a screening test using immunoassay analysis. This test is followed by a gas chromatography/mass spectrometry (GCMS) for confirmation purposes if the screening test is positive.

Sample substitution or adulteration has become a significant issue in the United States due to the prevalence of synthetic and/or drug-free urine and a wide range of adulterants available on the internet.

Some people attempt to defeat a urine test by drinking copious amounts of water. However, a sufficiently diluted sample can be detected by measuring specific gravity creatinine. If the sample fails to meet specific gravity and creatinine standards, the sample is reported as dilute.

The urine specimen can even be reported as "Invalid" if the specific gravity and/or urine creatinine is very low. Department of Transportation (DOT) regulations require a recollection if the sample is invalid.

Substituted specimens are those that are inconsistent with normal human urine. Some people try to add substances to the urine to mask the detection of drugs.

Certain tests can be ordered to try to identify specific adulterants and ensure the tests that are collected are accurate.