How Does a Urine Drug Test Work?

 Urine Drug Test:

Urine drug tests use a dipstick soaked with antibodies that react with THC. Test strips are inserted into the urine sample. Urine moves up the dipstick by absorption (capillary action), and the antibodies on the dipstick change color if any THC is present in the urine.

The sensitivity level for most urine drug tests is set at 50 ng/mL, although some tests may be more sensitive. Urine drug tests typically require at least 30ml/urine and are over 99% accurate, so if your urine contains detectable amounts of THC, there is little hope of cheating the test.

What drugs can a urine drug test detect?

A urine drug test can detect:

Cocaine,

Methamphetamine,

Benzodiazepines,

Marijuana,

Opiates,

Barbiturates,

Pentachlorophenol,

Methadone,

Oxycodone, and

Ecstasy.

How Long Can You Test Positive for Marijuana in Your Urine?

Most people can test positive for up to 2 weeks with casual use and 30 days with extreme heavy use. This mainly depends on the frequency of use and sensitivity of the test. Generally speaking:

Most recreational marijuana use, once or twice a week, was detectable for up to two weeks after consumption with a test device that detected 50ng/mL.

Daily users occasionally test positive at 50 ng/mL for up to 30 days.

Very heavy use with multiple daily use was rarely detected at 20 ng/mL for up to 60 days.

In the rarest case, an obese person with a slow metabolism who uses marijuana several times a day may test positive in urine at 20 ng/mL for 90 days or more, but this is almost unheard of.

A popular fact sheet for drug court practitioners’ claims that even heavy marijuana use can only be detected within two weeks, with detection after 30 days extremely rare. But the argument was written by an author who argued that some extreme examples of longer testing times were used as an excuse to cover up recent drug use.

While this argument may be true, if you want to pass a drug test, just two weeks of cleaning isn't the best way to go. Detection times over 70 days have been recorded at 20ng/ml. Therefore, if you have enough time and are a heavy user, it is best to abstain and cleanse for 30 to 60 days before the test to ensure your urine is really clean.