Urine drug tests, or UDS, are used to analyze urine for the presence of certain illegal drugs such as cocaine, amphetamines, methamphetamines, opioids, and marijuana.
These drug tests are most often used for potential employees because employers want to ensure the person they’re hiring is reliable and sober. Employees who use illegal substances miss work up to 20-times more often than those who don’t.
But just how do drug test kits detect certain drugs in urine, and are they really reliable?
How Urine Drug Tests Determine Drug Use
Urine analysis for drug use is the most common type of drug test used by potential employers. The urine is screened specifically for the presence of a parent drug, such as heroin, or its metabolites, such as morphine. Metabolites are the modified form of a drug when the body has metabolized it.
The parent drug or metabolites are screened for through immunoassay, which is when the urine is analyzed for a substance’s antigens or antibodies.
Urine naturally rises because of surface tension. If a drug is present in the urine, its proteins will bunch together and a colored line shows up in the est line area of a drug strip.
The presence of either the parent drug or its metabolites doesn’t determine when a person has taken the drug or how much of it was taken. For this reason, the drug test results come back either positive or negative.
Are Urine Drug Tests Reliable?
A false positive on a urine drug test is rare, but it can happen. This is because immunoassays test the urine for antibodies rather than the drugs themselves.
If a person is on a prescription medication, it can sometimes cause the urine drug test to come back with a false positive for illegal substances. A potential employer or medical professional may be notified if the hire is prescribed with a medication which could impact their urine test.
In case a false positive is claimed, the potential employee can retake the test for an accurate result. If a urine test rarely gives a false positive, the chance of a urine test coming back with a false positive twice isn’t likely.
Urine drug test results are reliable for those who want to test potential employees for illegal substances before officially hiring them.