Types of THC Tests (and what the check for)
Although one may not die or experience permanent damage from consuming too much cannabis sativa, it has other toxic side effects. It's no wonder most federal governments prohibit the drug.
Also, most government institutions and companies require candidates to undergo a drug test before they can get employed. Until the war on drug abuse is over, we have to deal with these regulations, in as much as it sounds like an invasion of our private lives.
There are several types of tests done to detect the presence of THC in the human body. Below is a list of some of the most common methods used.(1)
Urine Drug Test
This is the most commonly used method. Basically, after collecting a urine sample, the lab checks whether it's a real urine specimen as there's quite a huge market for substitute urine. To determine whether the urine is real, they might look at the following characteristics:
- The temperature of the urine
- Color and appearance
- Creatinine – a protein mechanism by-product
- Space gravity to ensure the urine hasn't been diluted.
- Adulterants – any substance added to urine to fool the test
Urine drug tests for marijuana don't normally test for the presence of THC itself since the minimal amount is actually excreted into the urine. They instead test for metabolites of THC. These metabolites stay detectable in urine for much longer.
Usually, two types of tests are conducted that can assess the use of marijuana. The first one is the immunoassay test. It's as a rapid screening test that can be compared to home drug testing kits. In as much as this test is cheap, it can, at the time, produce false results. This is why most companies are forced to use the GC-MS test.
The GC-MS test is an extremely confirmatory test. It uses costly equipment and consumes more time. As a result, it produces up to 99% correct results. (2)
Unlike urine tests, saliva tests detect the presence of THC and not its metabolites. However, the test is conducted in a shorter period since THC doesn't stay so long in saliva. If a saliva sample is tested about 72 hours after intake, the detection level can be as low as 0.5 ng/ml. On the other hand, if the test is done immediately or 12 hours after consumption, the detection level can be up to 50 ng/ml.
The use of marijuana can as well be detected through hair tests. Hair test generally takes about 1.5 inches of growth. In such a case, the detection period is approximately 90 days. If the individual's hair happens to be shorter than 1.5 inches, the detection period becomes shorter.
Compared to head hair detection window, the detection period for body hair testing is longer. This is because body hair grows slower than head hair. Hair drug tests measure the THC embedded inside the hair shaft, and remove external contamination as a source of a positive result.
Marijuana stays detectable in the blood for about 12-24 hours. However, frequent or heavy use can be detected for up to 7 days. Blood tests aren't mostly carried out because they aren't only hard to administer, but are also quite invasive. They are primarily used in accident investigations to determine whether a driver was under the influence while on the wheel.
This test is mostly conducted to monitor individuals who are under probation or those involved in child custody cases. Usually, a sweat patch is fixed to the skin for about two weeks. The patch detects the presence of drugs excreted by the individual through sweat.
These are some of the most common THC detox tests done. Essentially, this article is for companies looking for the best way to carry out marijuana tests.