Cannabis Drug Testing

Cannabis is highly detectable and can be found in urine, saliva, hair as well as nail clipping samples. The tests available to determine cannabis use vary in their windows of detection so recent or chronic use can be established. In addition, ingestion as opposed to environmental exposure can be discerned.

Drug testing cannabis with urine

Urine drug testing is the quickest way to establish whether someone is misusing cannabis. The donor provides a sample of their urine in a fully-contained screening pot, which is then analysed for particular substances. This method is ideal for on-site testing thanks to it being quick, accurate and providing an immediate result. Urine drug testing is known as a ‘narrow-window’ form of testing as its period of detection is only a few days, although this can depend on the particular substance taken. Most drugs will be flushed out of a person’s system in a matter of days. Drugs including cocaine, MDMA and methamphetamine can be present in urine for roughly 3-5 days, but cannabis can stay in urine for as long as 28 days after chronic use.

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Drug testing cannabis with oral fluid

Oral fluid drug testing involves analysing a sample of saliva. The entire test takes 20-30 minutes and involves placing an absorbent collection device (similar to a large swab) inside an individual’s mouth for a few minutes to soak up sufficient saliva. This is another ‘narrow-window’ form of testing and is therefore a quick test to determine recent cannabis use. Its period of detection is approximately 30-60 minutes after ingestion – up to 48 hours – although, again, this can depend on the particular substance taken.

Drug testing cannabis with hair

Hair drug testing is used to provide a more comprehensive overview of a person’s cannabis use. This is known as a ‘wide window’ form of testing as it can determine a history of drug intake for up to 12 months. After cannabis is absorbed into the bloodstream, metabolites are absorbed through the root of the hair and become embedded in the hair shaft. These metabolites remain in the hair as it grows, hence it is a suitable method for detecting a person’s historical cannabis intake.

By segmenting head hair samples into monthly 1 cm sections, a month-by-month profile of drug use can be attained. Analysis of small segments can help establish a positive hair test in a narrow timeframe, but unlike saliva and urine tests, hair strand analysis cannot show recent drug history. It can take between 7-10 days for the hair containing the drug to grow above the scalp.

Environmental exposure to cannabis can also be detected using hair strand analysis. If an individual has been in an environment heavily laden with smoke, for example, each hair sample is chemically washed three times to remove or reduce any drug present prior to analysis. If a donor admits to being surrounded by cannabis smokers, the washing solution could be used to back up any test results.

Drug testing cannabis with nail clippings

Cannabis can be detected in nails because when it is consumed, its metabolites circulate in the bloodstream. These substances pass from the blood vessels below the nail into the keratin fibres as the nail grows. They then become trapped and can thus be detected. Either fingernails or toenails can be used for the test, but not a mixture. Approximately 10 mg of nail is required in total and they need to be collected as close to the nail bed as possible.

Unlike hair drug testing, nail drug testing won’t give a historic segmented pattern of drug use, but it will give an overview of up to 12 months. For information on any of AlphaBiolabs’ home drug testing kits, please email us at

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