Marijuana is one of the most illegal drugs in use today. Marijuana drug test is common at schools, home and workplaces. This is done through various methods including blood, urine, saliva, and hair. The presence of tetrahydrocannabinol (THC) which is the main active component of marijuana, and its metabolites are detected by these methods. However, a saliva test detects THC and not its metabolite.

The time of detection of marijuana is based on certain factors. These include kind and sensitivity of the test performed; frequency, dosage, and last time of use of drug; genetic makeup of an individual; metabolic rate of a person; and other random factors. The detection time varies for different types of drug tests.

Marijuana is generally taken in through smoking or ingestion. If it is ingested, usually a time of 20 minutes to an hour and a half is taken for the drug to be absorbed into blood. When marijuana is inhaled through smoking, it rapidly enters into the bloodstream. Hence THC can be detected within a few hours in blood. Later it gets converted into metabolites which are stored in body fat and then eliminated through urine or feces.

THC can be detected for 4-8 hours after smoking in case of frequent users through blood tests. However, the byproduct through blood tests, can be detected up to two weeks after smoking in case of frequent users. Among infrequent smokers, the detection time for marijuana through blood tests for THC is 3-4 hours after smoking and 2-3 days for its by product.

The THC byproduct is detected in urine for 2 weeks to 30 days after smoking among frequent smokers and up to 10 days after smoking among infrequent smokers.

The drug detection time for marijuana by saliva test is not validated. However, it can be detected up to two hours after consumption.

Hair tests conducted for marijuana testing can detect the drug for a long period of time. As the drug gets deposited in the hair shaft, the drug can be detected for about 90 days among frequent drug users.

Hence based on the type of test used, the detection of marijuana can be varied. A proper choice of method should be made while conducting marijuana testing at workplaces.