A biological specimen, like blood, sweat, urine, saliva or hair, is used for technical analysis when testing for the drug cannabis. The biological specimen will show the presence of the cannabis ingredients (usually THC) or the metabolites (the products broken down).
People use cannabis testing kits to check if individuals are using the drug. The accuracy differs depending on the type of tests and the timing of it. It is possible to detect the drug for up to 90 days after using. While the tests are common place, many do not understand the way that they work.
What does the Cannabis Drug Test Detect?
Cannabis produces a psychoactive effect on a person. This happens due to the chemical Tetrahydrocannabinol (THC). The drug is stored within the fat after going into the bloodstream and breaking down.
How long does the THC stay in your system?
The length of time THC remains in the system depends on a number of factors. It will depend on the amount of drug used, the duration that it is used over and the frequency. It is possible that the quantity varies so some samples are more potent and will last longer than others, even when other factors are the same.
The Different Forms of Cannabis Drug Tests
The cannabis metabolises throughout the system and is excreted through the urine, into the blood and through the follicles in the hair. There are now three forms of testing to use on the saliva, blood, hair and urine.
The Urine Test: This is the most common of all Cannabis Drug Tests where individuals will have to urinate into a cup to provide a sample. This is screened at 50 nanograms, the threshold sensitivity level, to test for the THC metabolites. When there is more than 50 nanograms in a millilitre, it will show positive for the drug. Depending on the frequency of usage, it is possible that the drug can be detected for 30 days. Those who use it heavily will find that it usually appears for up to 15 days, while those who use it infrequently will find that it is there for between two and five days. Chronic users and those with more body fat will find that it can be detected for the full 30 days.
Urine-based Cannabis Drug Tests are the most common form of Cannabis Drug Testing and can be bought as single parameter drug tests, that check for the presence of THC alone, or multi-parameter drug tests that can pick up Cannabis as well as many other common drugs of abuse. Multi-parameter drug tests can detect up to 12 different types of drug.
The Saliva Test: Saliva tests are sensitive and offer some of the most accurate results. There are different types of saliva tests, which change the accuracy gained. It is possible to get a positive result within minutes from the saliva and detection time is up to 48-72 hours from last drug use. Saliva drug tests are more expensive than urine drug tests and the choice of tests is less extensive. Often a saliva drug test for home use will be sold as a multi-parameter test that also screens for other drugs of abuse.
The Blood Test: THC is not the only thing tested for with blood samples; they look for the chemical residue and other drug components. It is possible to get a positive result up to three days after using the drug. This test needs to be carried out in a lab and it is the most invasive of options.
The Hair Test: These tests are done on the follicles, after new hair has grown through. 2-4 cm of hair is needed for these tests and it can show cannabis use for up to 90 days after use.
Best Cannabis Drug Testing Kits
This post has been updated since its original publication in 2013.