Four Major Drug Tests And Their THC Detection Times

You may be wondering how far back the drug tests can detect marijuana use (it’s especially important if you’re an employer).

Here are a couple of caveats, before getting to the facts:

Detection time depends on what type of test is used, the equipment used (it isn’t all the same), and sensitivity of the specific test process. The following are other factors that can affect a drug test’s accuracy for marijuana use:

– Digestive system of the user (if the marijuana is ingested)
– Metabolism of the user (but not to the extent the many individuals think)
– The last time and date of use
– The concentration/dosage of THC
– Frequency of use

Reduction In Blood Levels Over Time

If you smoke marijuana, your THC blood level has a tendency to spike quickly and then drop below 50 ng/mL, which is the regular drug test threshold level.

If you consume hash brownies, the level of THC will build gradually over time, with its peak being in around 4 hours.

It takes much longer for THC to dissipate. It the metabolite that is used for detecting marijuana in a majority of drug tests.

Hair Test For Marijuana

The development of the hair drug test was for the purposes of identifying long-term use instead of infrequent use or one-time use.

It is possible for a hair follicle drug test to detect marijuana beginning in about 7 to 10 days after marijuana is first used.

Mass spectroscopy is used by test labs for detecting the presence of the metabolite THC-COOH, which is a non-psychoactive THC-byproduct. The cutoff level that a majority of tests consider to be a positive result for usage of marijuana is a TCH-COOH concentration of 50 ng/mL or higher.

A hair follicle test is a lot less likely to detect a one-time (or infrequent) user of marijuana.

A Forensic Science International study that was conducted in 2006 found that 85% of individuals who used marijuana on a daily basis tested positive for THC usage. However, just 52% of those who smoked used marijuana one to five times on a weekly basis were detected by the test.

Also, ingesting or eating THC lowers the chances that you will be detected.

Urine Test For Marijuana

The urine test is the most popular type of THC drug test that is used today.

Since it takes a very long for THC-COOH to be eliminated from the body, it results in a urine test being more sensitive to marijuana compared to other types of drugs that are commonly used. That is the reason a urine test is the preferred type of test to detect marijuana use. Urine tests, like hair tests, look for metabolite TCH-COO. The cutoff is usually at 50 ng/mL for these tests.

Urine tests can detect marijuana for days or sometimes weeks after it has been used. Marijuana can be detected for days after it has been used and the high is long gone, even in first-time users.

In a recent study of one-time THC users, the most striking thing to come out of the study was how the results varied so much from one individual to the next, and even hour by hour.

For example, Subject B was clean for two days, while Subject E was completely safe the whole time. Depending on what time of day it was, Subject G might have failed or passed the 50 ng/mL cutoff for the test.

The main reason for the wide variability is the THC-COOH concentration that is in your urine is quite subject to how much water is inside your body as well as your body’s metabolism and urine. If you have a low metabolism or are poorly hydrated, it is more likely that you will fail your urine test.

When it comes to the urine test, the bottom line is that to be safe, the best thing to do is assume you’ll fail the test if any amount of marijuana is used within a couple days of taking the test.

Blood Test For THC

The most accurate type of marijuana drug test is a blood test. The reason for that is because measures THC’s direct presence within your body’s system.

However, blood tests are only able to detect drug use that has occurred within a couple of days. They are mainly used for investigating accidents as well as crimes that have been committed under the influence.

Blood tests also are often ordered in parole and domestic dispute situations, where abstinence has been ordered by the court.

Saliva Test For Marijuana

Saliva tests aren’t typically used for detecting marijuana use in the United States because of poor results.

The major problems with performing saliva tests for THC, as a large-scale industry research project from 2006 called the Rosita Project reported, include:

– Devices that read the test results malfunctioning
– Difficulties in obtaining a sufficient amount of saliva

It is possible, and maybe even likely, that the technologies and methods employed by test device manufacturers will keep improving.