Drug testing for marijuana

Marie Law Alphabiolabs

By Marie Law, Head of Toxicology at AlphaBiolabs
Last reviewed: 02/13/2023

Marijuana is among the most misused substances in the US.

It is also highly detectable using drug tests and can be found in urine, saliva, and hair, as well as nail clipping samples.

In this article, we discuss marijuana drug testing, and how marijuana can be detected by different drug testing methods.

How long does it take for marijuana to show up in a drug test?

Marijuana use can be detected by a drug test long after the drug was first consumed.

There are a variety of drug testing methods used to test for the presence of marijuana, including oral fluid (saliva) drug testing, urine drug testing, hair drug testing and nail drug testing.

Oral fluid and urine drug testing are known as ‘narrow-window’ forms of testing and can be used to detect drug use from approximately 30 minutes after consumption, up to a few days.

However, this can vary depending on the type of substance and how much was used.

The rate at which hair and nails grow means that both hair drug testing and nail drug testing can provide a ‘wide-window’ of detection for drugs and their metabolites (up to 12 months).

Urine drug testing for marijuana

Urine drug testing is the quickest method for determining whether someone has been using marijuana.

This type of drug test involves collecting a sample of the donor’s urine in a self-contained screening pot, which indicates the presence of substances via built in test strips.

The results of the test are visible on the side of the pot within a few minutes.

This rapid form of drug testing is ideally suited where an immediate result is required and is known as a ‘narrow-window’ form of drug testing.

Urine drug tests can detect a single use of marijuana for up to four days after it has been consumed. Chronic heavy use of marijuana can be detected up to 30 days after being ingested using the same urine drug testing methods.

Order a Home Urine Drug Test Kit Online

Oral fluid drug testing for marijuana

Oral fluid drug testing is a type of drug test that can be used to detect the presence of drugs in a saliva sample.

The test involves placing an absorbent collection device (like a large swab) inside a person’s mouth for a few minutes, to soak up enough saliva for analysis.

As with urine testing, oral fluid drug testing provides a ‘narrow-window’ of detection and is ideal in instances where a rapid test is required to determine marijuana use.

The test can detect marijuana use within approximately 30 minutes of consumption, up to 48 hours.

Hair drug testing for marijuana

Hair drug testing – also known as hair strand testing or hair follicle testing – works by analyzing a cut hair sample (head hair or body hair) for the presence of drugs and their metabolites.

This is known as a ‘wide-window’ form of drug testing, enabling us to determine a history of drug use for up to 12 months after consumption.

When a person takes drugs, they are broken down by the liver and a proportion of the drug and its metabolites are released into the bloodstream.

These drugs then enter the hair follicle and become trapped in the medulla, the innermost layer of the hair shaft. These substances remain trapped in the hair as it grows, making hair drug testing an effective method for determining a history of marijuana use.

Nail drug testing for marijuana

Nail drug testing is known as a ‘wide-window’ form of drug testing, enabling us to determine a history of marijuana use for up to 12 months after consumption.

When a person takes drugs, they are broken down by the liver and a proportion of the drug and its metabolites are released into the bloodstream.

These substances then pass to the blood vessels below the nail, and into the nails themselves where they become trapped in the keratin fibres of the nail.

Fingernails and toenails grow at different rates, with fingernails providing an approximate six-month overview of drug use, and toenails providing an approximate 12-month overview.

Nail testing is an extremely reliable method for determining whether a person has used drugs in the six- or- 12-month period prior to the samples being collected.

Order a Nail Drug Test Kit

Home drug test for marijuana

We offer a range of home drug test kits designed to give you peace of mind or enable you to seek support for a loved one who is struggling with substance misuse, including marijuana misuse.

  • Home Urine Drug Test Kit (pack of 3 – $34.95) – this easy-to-use home drug testing kit can detect drugs and their metabolites in a urine sample. The self-contained screening kit includes built-in test strips, allowing you to read the results in just 5 minutes
  • Drug and Alcohol Nail Test (from $99) – this test can detect drug use for a period of up to 12 months prior to samples being collected, with only a sample of fingernail clippings or toenail clippings required. Simply follow the instructions included in your test kit to collect your nail clipping samples and return them to our accredited laboratory for testing

Please be aware that our home drug test kits are for peace of mind only, and the results cannot be used in court or for legal reasons.

For confidential advice about which test might best suit your needs, you can email our Customer Services team at info@alphabiolabsusa.com.

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Marie Law AlphaBiolabs

Marie Law

Head of Toxicology at AlphaBiolabs
A highly-skilled and respected scientist with over 13 years’ experience in the field of forensics, Marie joined AlphaBiolabs in 2022 and oversees the company’s growing toxicology team. As Head of Toxicology, Marie’s day-to-day responsibilities include maintaining the highest quality testing standards for toxicology and further enhancing AlphaBiolabs’ drug and alcohol testing services for members of the public and the legal sector.

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