How Long Can THC Be Detected in the Urine?

With THC being the primary chemical compound found in marijuana, it is important that you understand how long it stays in the system to plan for when you get tested in order to come out clean. This is because once you ingest marijuana into your body, it quickly enters into your bloodstream and begins to break down. The amount of weed a person uses or has ever used is a determining factor of how long drug tests can detect THC in your system. There are several methods through which THC metabolites are tested.

How Long Is THC Detectable in Urine?

Tests for THC in the body can be divided into two categories. The first category, including hair test and urine test, is for habitual weed users. It is this test that detects whether a person has used weed in the past or not. The second, including blood and saliva test, is that of people currently under the influence of marijuana

Urine Test

This is the most commonly used drug test. The test is quite easy and all that is required is a sample of urine by the subject for the test to be carried out. The sample is first taken to the laboratory then screened under the threshold sensitivity level. If the targeted metabolites of the test are found to be higher than 50 ng/ml, there is a high probability of testing negative, and hence being marked as a “suspect” until the test is completed.

Once a sample test is marked suspect, the test is repeated again with the use of more advanced test kits such as Gas chromatography/mass spectrometry. However, the test is analyzed under a threshold of 15 ng/ml, which makes the result very accurate.

How long is THC detectable in urine? If you are a chronic marijuana user, THC can be detected in your system using a urine test for up to 12 weeks depending on the quantity as well as frequency of use. Note that if you just used marijuana once and stopped, you can still test positive to a drug test. This is because the test can detect THC metabolites in urine 48 to 72 hours after use. You can go to the following site to get more accurate results based on your age, gender, weight, smoking frequency and marijuana potency.

Hair Test

Though hair test is more accurate compared to the other tests, it is relatively expensive and not reliable especially if a person only used marijuana once in the past. Well, with the rise in crimes and issues about legalizing marijuana, more and more companies are using the test. This is because the test can be used to detect the use of marijuana even months later on. Just an inch of hair from a person’s scalp is all specialists need for the test. Also, hair from any other part of the body can still be used. This includes hair from the pubic area, arms and legs.

Saliva Test

This is the newest test for marijuana usage and hence not commonly used. Usually, it is used to investigate car and work accidents. This is because the test can detect whether a person is under the influence of marijuana or not. A saliva test can produce positive results within the first 24 hours of its usage.

Blood Test

This is yet another test used to detect current usage of drugs such as marijuana. It also helps to investigate car/work accidents. The only difference between the saliva and blood test is that blood tests are more common than saliva tests, which are not fully established. For a single use of weed, the blood test can produce positive results for 6-24 hours. This is so unfortunate especially for people who are used to marijuana. Worse yet, a blood test can still produce positive results for up to 7 days.

Despite the fact that the above tests are likely to detect weed in your system, truth is that it is not easy to tell after how long THC metabolites can be detected in your system with absolute analysis due to the fact that there are numerous variables likely to affect the results. It is for this reason that the table below was created to clearly show how the drug test calculator works.

Table: Drug Test Types and Approximate Detection Times

To Detect Present Intoxication

To Detect Past Use





Marijuana - Single Use

0 - 24 Hours

6 - 24 Hours


Drug Test Calculator

Marijuana - Regular Use

0 - 24 Hours

Up to 7 Days

Months to Years

The above is as a result of collecting drug test data from thousands of marijuana users over the past years and is exactly the way a calculator test will show.