Marijuana (cannabis) Urine Test

You may be asked to take a marijuana urine test as a part of the hiring process for a job. Since marijuana is illegal to use and may have severe effects on your health, many hiring committees require the person to undergo drug testing.

This test is also ordered for individuals who show signs of drug toxicity or abuse. Some side effects of the cannabinoids in marijuana are as follows:

• Slowed digestion
• Bloodshot eyes
• Muscle relaxation
• Drowsiness
• Fast heartbeats
• Depression
• Low blood pressure
• Paranoia
• Hallucinations

Additionally, this test would be used to monitor the treatment of drug abuse and to check for relapse.

You don’t have to do any special preparation for this test. 

Notify your doctor if you are taking any medications, vitamins or herbal supplements. Some cough and cold medicines, antibiotics, ibuprofen and the nausea medicine dronabinol can affect the results of this test. 

The lab facility will give you a special container to collect a sample of your urine. They will let you know if there are any specific protocols to be followed. 

In case the test is to be used as legal evidence, a witness may be present during urine collection to prevent any contamination or cheating on the test. 

Normal results:

Normal results in the case of the marijuana test are reported as negative. It means that no metabolite of marijuana was detected in the sample provided, or the amount detected was much below the cut-off value.

Generally, the cut-off value is 3.0 ng/mL, although it may vary from one laboratory to another. A cut-off value separates the negative results from positive. Any value below this is considered negative and any value above it is considered positive. 

Sometimes, a check for the presence of tetrahydrocannabinol carboxylic acid (THC-COOH), a major metabolite of delta-9-THC, is also performed on the sample. The results will be considered normal if the value for this test is below 15.0 ng/mL.

Abnormal results:

Results for this test are considered abnormal (and positive) when the amount reported in the urine is higher than the cut-off value.

A confirmatory test may be performed for checking the presence of another metabolite, THC-COOH, which can be detected in urine for more than 7 days even after one use. If the values of THC-COOH are above 100 ng/mL, then it is an indicator of recent marijuana use, mostly within the last 7 days. Values higher than 500 ng/mL can point towards recent and chronic use. 

Since the THC-COOH metabolite of marijuana can stay in the body for a longer duration, the test is extremely helpful as a confirmatory test even 30-60 days after chronic use of the drug.

Based on the test results, you may be required to undergo further drug testing or testing of other fluids such as saliva, blood or sometimes, even hair.

(Read more: Marijuana blood test)

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.