Back To Top
mghealth.com coliquio.de coliquio.de tsv1860.de

How long can THC be detected in blood and urine?

Many patients receiving medical cannabis wonder how long cannabis can be detected in urine and blood. This fact could be of significant importance for some patients when performing certain professions and/or driving a motor vehicle. To answer this question, it is helpful to first look at the mechanism of action of the ingredients of cannabis and how they are metabolized in the body. In addition, it is important to understand which cannabinoids and corresponding degradation products are important in drug testing.

How long does cannabis stay in the body?

Cannabis contains about 100 cannabinoids. One of the most important of these is tetrahydrocannabinol (THC). It is responsible for the psychotropic effect of cannabis. When determining the period of time during which THC is detectable in the various tissues and organs of humans, its degradation products must also be taken into account. Their half-life can be up to several weeks, so THC can be detected with various tests over a long period of time.

Depending on the method of ingestion, the duration of the acute effect of medicinal cannabis is as follows:

  • for inhalation: 1-3 hours (1)
  • if taken orally: up to 8 hours (2)

A number of factors influence how long cannabis can be detected in the body (3):

  1. The amount of cannabis ingested: the more cannabis is ingested, the longer it remains in the body.
  2. Genetics: A person’s genetic profile can have a major impact on how long cannabis stays in the body. This is due to the genetic variability of the enzymes that break down cannabinoids.
  3. Frequency of use: The more frequently cannabis is used, the more THC accumulates in the blood due to its cumulative effect.
  4. Body fat: The volume of adipose tissue has a directly proportional effect on how long THC can be detected in the body due to its high fat solubility.
  5. Metabolism: The faster a person’s metabolism is, the faster cannabis is excreted from the body and vice versa. This is influenced by a person’s lifestyle.
  6. Type of test: The type of test used to detect cannabis metabolites greatly affects the detection window. While rapid tests only detect the presence of a psychoactive substance, more accurate and in-depth laboratory tests can determine the type and frequency of use.

How long can THC be detected in urine?

The most common way to detect THC is by urine test. Cannabinoids and their metabolites take a very long time to be excreted from the body via the kidneys. Thus, they are detectable in urine for considerably longer than if they were to be detected in blood plasma. Provided cannabis has been consumed only once and in small amounts, it can be detected within 1.5-3.5 days(4). In this case, the main degradation product of THC, the carboxylic acid THC-COOH, is determined. This acid form of THC is not identical to the one originally formed in the cannabis plant. Regular use has a significant effect on how long cannabinoids and their degradation products are detectable in urine. In the case of very heavy consumption, this period can be up to 30 days (5).

How long is THC detected in the blood?

In blood plasma, cannabinoids remain for a much shorter period of time. For example, THC from inhaled cannabis with a low THC concentration is undetectable after about 7 hours, whereas this is not the case for cannabis with a high THC concentration until after about 12 hours (4). At the same time, the degradation product THC-COOH remains detectable in the blood for 3.7 days with infrequent cannabis use and 6.2 days with frequent use (4).

How long can THC be detected in hair?

This method of determining the presence of cannabinoids in the body is the least used because of its unreliability. THC metabolites can be detected even in the absence of cannabis use because they are transmitted through cannabis smoke.(6)

Hair testing can be used to determine the likelihood of cannabis use over time. The detectability of THC can be up to 90 days as THC-COOH penetrates the matrix of the growing hair (5). As long as the hair is alive and continues to grow, it is possible to detect the THC metabolites.

Conclusion

Traces of cannabis remain in the body for some time after ingestion and can be detected by a simple rapid test or laboratory analysis. How long they are detected depends on several factors, including the person’s condition, the type of use, and the type of test. Practice shows that cannabis is detected in blood for a shorter time than in urine, with the longest retention time in hair. The results of such tests often have a significant impact on a person’s life, even when cannabinoids are used for therapeutic purposes under a doctor’s prescription.

Sources

1. Abuse NI on D. What are marijuana’s effects? [Internet]. National Institute on Drug Abuse. — [cited 2023 Jan 9]. Available from: https://nida.nih.gov/publications/research-reports/marijuana/what-are-marijuana-effects

2. Schlienz NJ, Spindle TR, Cone EJ, Herrmann ES, Bigelow GE, Mitchell JM, et al. Pharmacodynamic dose effects of oral cannabis ingestion in healthy adults who infrequently use cannabis. Drug Alcohol Depend. 2020 Mar 21;211:107969.

3. Arbuckle A. 6 Factors That Influence How Long Cannabis Stays In Your System [Internet]. SureHire | Occupational Health Testing. 2021 [cited 2023 Jan 9]. Available from: https://www.surehire.com/6-factors-that-influence-how-long-cannabis-stays-in-your-system/

4. Musshoff F, Madea B. Review of biologic matrices (urine, blood, hair) as indicators of recent or ongoing cannabis use. Ther Drug Monit. 2006 Apr;28(2):155–63.

5. Hadland SE, Levy S. OBJECTIVE TESTING – URINE AND OTHER DRUG TESTS. Child Adolesc Psychiatr Clin N Am. 2016 Jul;25(3):549–65.

6. Moosmann B, Roth N, Auwärter V. Finding cannabinoids in hair does not prove cannabis consumption. Sci Rep. 2015 Oct 7;5:14906.

Information for doctors and pharmacies

Information for doctors and pharmacies
Buy medical cannabis

General information on medicinal cannabis

General information on medicinal cannabis
Cannabis products
So kaufen Sie medizinisches Cannabis in Deutschland?
Seit dem Inkrafttreten des „Cannabis als Medizin” Gesetzes am 10. März 2017 ist die Verschreibung von Cannabis in Deutschland zu therapeutischen Zwecken legal. Unter ärztlicher Anleitung können Patienten ein Rezept für medizinisches Cannabis erhalten und damit medizinisches Cannabis in verschiedenen Formen erhalten und anwenden.
Weiterlesen