A Guide to Cannabis Drug Testing

In our ongoing series on drug testing, we've explored the intricacies of Ketamine and Cocaine drug testing and its relevancy in legal scenarios. Today, we are looking at another widely used illicit drug - Cannabis.

Cannabis (aka marijuana, weed, dope, grass, hash etc.) is a well-known Class B drug that carries a number of severe legal consequences (if not prescribed by a specialist doctor) for possession, supply, production, import and export under the UK Misuse of Drugs Act 1991.

As cannabis is a Class B drug, the maximum penalty for possession is five years imprisonment and additionally, a magistrate’s court can impose a fine of up to £2,500. If you are prosecuted for supplying or producing an illicit drug like cannabis within the UK, the prison sentence can be up to 14 years.

Cannabis addiction and abuse in the UK remains a prominent issue with a staggering 14 million people having reported to have used the drug before, making it the most popular illicit drug in the UK.

In this article, we delve into various aspects of cannabis drug testing, answering FAQ questions such as:

- Will cannabis show in a drug test?
- How long does cannabis stay in your system?
- What types of methods are available for cannabis testing?
- What factors influence cannabis detection?
- Why might a court-ordered cannabis test be necessary?
- What happens if a cannabis test comes back positive?
- We’re here to help

Will cannabis show in a drug test?

Yes. Cannabis, like the other drugs we have discussed, is detectable in tests. However, similarly, the results can vary depending on the specific test type, the timing of the test and the individual being tested.

How long does cannabis stay in your system?

The length of time the effects of this drug last depends on how much you have taken, the method of consumption, and whether you have taken any other drugs. The “high” from cannabis typically last 1-4 hours. However, traces of the drug can persist in the body for an extended period, as indicated by the various testing methods we will discuss.

Detection timeframes for different types of tests are listed below:

Body System	Time in System
Blood	24 to 48 hours
Saliva	24 to 72 hours
Urine	1 to 30 days
Hair	Up to 12 months

What types of methods are available for cannabis testing?

At DNA Legal, we provide a range of testing approaches for identifying cannabis use. Much like the other drugs we have explored, there isn't a dedicated test solely for cannabis. Instead, our drug tests are designed to detect any traces of substances present in the individual's system.

The Hair Test: Up to 12 months

As THC makes its way into hair follicles via the bloodstream, hair testing is a popular method and advanced hair drug testing can detect cannabis in the body for up to 12 months (depending on hair length). What makes this method stand out is its ability to unveil a detailed month-by-month record of drug usage over a 3 to 12-month timeframe.

Each 1cm section of hair offers a window into the drug use during that specific period so if the individual has 6cm of hair, 6 months can be tested. While it's a powerful tool for assessing long-term cannabis use, it's essential to note that there's a waiting period of up to three weeks after consumption before traces of the drug show up in hair, making it less effective for detecting recent use.

The Urine Test: 1-30 days

Urine tests are a common choice for identifying cannabis use and provide a detection window spanning from a few days to as long as several weeks after the last use. Nonetheless, this timeframe can differ based on factors like an individual's metabolism and the amount of cannabis they've consumed.

According to the Mayo Clinic Proceedings’ Clinical Interpretation of Urine Drug Tests the general guidelines for urine testing suggest detection times per use:

- Single-use: up to 3 days after last use

- Moderate use (4 times a week) up to 5-7 days after last use

- Chronic use (daily): up to 10-15 days after last use

- Chronic heavy use (multiple times daily): up to 30 days after

Urine tests are frequently favoured in legal and clinical contexts because of their comparatively longer detection window and precision, making them the most prevalent choice for cannabis detection

The Blood Test: Detection from 24 to 48 hours

Blood tests are a remarkably reliable means of detecting recent cannabis consumption. Their peak accuracy occurs within the initial 24 hours after use, but they continue to show valuable insights for up to 48 hours. Additionally, in cases of heavy or chronic use, blood tests may detect use up to 30 days.

These tests are often administered alongside urine tests to give a more accurate reading into the individual’s drug use.

The exceptional precision of blood tests ensures that precise information can be provided to healthcare professionals and legal authorities, making them a valuable tool for time-sensitive evaluations of cannabis use.

The Saliva Test: rapid detection from 24 to 48 Hours

The saliva or oral test offers a swift and efficient means of detecting recent cannabis use, usually delivering results in just 20-30 minutes after a simple swab.

This test is commonly employed in criminal cases, especially when law enforcement needs to establish whether an individual is under the influence of drugs.

It provides a relatively short detection window of 24 to 48 hours, making it ideal for identifying recent cannabis use. The test’s speed and ease of use make it a valuable resource for conducting on-the-spot cannabis assessments, for example, for police suspecting DUI.

What factors influence cannabis detection?

Several factors can influence how long cannabis remains detectable in your body, including:

Test sensitivity
THC dose consumed
Method of consumption
Gender
Hydration
Metabolism
Body mass/Body fat
Frequency of use

Why might a court-ordered cannabis test be necessary?

A court-ordered cannabis test may be required in various legal scenarios. One typical situation arises in criminal cases where drug use could be linked to the alleged offence. These tests serve as vital evidence in establishing whether a suspect was under the influence of cannabis during the incident in question.

Additionally, in family court matters, such as divorce or child custody disputes, suspicions of drug use can lead to court-ordered testing to ensure the well-being of the children involved. This helps to assess the environment and care the child will receive in addition to the conditions they may be exposed to, ultimately influencing custody decisions.

In essence, court-ordered cannabis tests serve as a tool to uphold the law, protect individuals' rights, and prioritise the best interests of children when necessary.

What happens if a cannabis test comes back positive?

If a court-ordered cannabis test returns with a positive result, it can trigger substantial legal and personal consequences. In a criminal case, a positive result can strengthen the prosecution's argument, potentially leading to charges or a conviction related to drug-related offences.

In the context of family court proceedings, particularly in child custody disputes, a positive test can influence custody decisions, often resulting in restrictions on visitation or supervised visitation arrangements, to ensure the child's safety and well-being is paramount.

However, it's important to understand that a positive test result doesn't immediately point to guilt or parental unfitness. In certain situations, individuals may seek rehabilitation and support to deal with their substance abuse concerns, affording them the opportunity to later petition the decision for reconsideration.

Ultimately, the response to a positive test outcome varies depending on the unique circumstances of the case and the individual’s willingness to confront their drug issues and seek help.