A question we are always asked at Zoom Testing is “How accurate are your cannabis drug tests?” We get asked this question quite regularly by people in all sorts of situations. A common scenario is that a person is scheduled for a drug test at work. For one reason or another, they have been using cannabis and are worried that a positive drug test will get them the sack. So they buy one of our tests beforehand to check that they are okay before the real test at work.
If our customer taking the drug test gets a negative result, they are often overjoyed. But then the doubt kicks in. Just how accurate was the test? Is it possible that I will get a positive at work when I got a negative on the home test?
In short, there is no need to worry. Generally, a drug test from us will give similar results to that of an employer drug test. How far the drug tests can check for, is based on the type of test it is – either urine, saliva or hair follicle testing.
How Accurate Are Urine Drug Test Kits for Cannabis?
Modern-day drug tests are very accurate. Typically, most drug testing kits will have an accuracy of between 97 and 99% when the manufacturer’s instructions are followed correctly. This is very high. Because most employment drug screening uses urine drug tests, it means that they are very hard to cheat.
Many will attempt to cheat a cannabis drug test by one of three methods: substitution, addition or dilution.
The first method means that a drug test for cannabis can be beaten by substitution of the donor’s urine with that of another person who is “clean” of drugs. Sounds simple, but it is not that easy! Often urine that is donated as part of a drug test is subjected to an adulteration test. These kinds of tests are designed to identify instances where fake urine has been used in a drug test.
Addition or dilution is when the urine sample is watered down or chemicals are added to the urine sample to try and produce a negative result. Once again, an adulteration test kit will show if the urine sample has been tampered with.
Urine drug tests for Cannabis are normally single drug test kits or one drug that is tested for as part of a multi-drug test kit.
How Accurate Are Saliva Drug Test Kits for Cannabis?
Many employers are now turning to saliva drug tests as a way of drug testing for cannabis. Tests that use saliva are often preferred now as they are much harder to cheat than urine drug tests. They also have fewer privacy issues. Accuracy of saliva drug tests for cannabis are also high, up to 99%. However, the testing window for saliva drug test kits is much lower than for urine tests.
Saliva drug tests for cannabis are normally multi-drug test kits that test for a number of drugs at once, of which cannabis is just one.
Saliva drug test kits for cannabis can detect the presence of THC, the active ingredient in cannabis, within hours of use. This means that if an individual consumed cannabis in the last 24-48 hours, there is a high chance that the saliva drug test will detect it. However, the accuracy of saliva drug tests for cannabis can be influenced by a number of factors such as the frequency of use, the amount of THC consumed, and individual metabolism.
One of the advantages of saliva drug tests for cannabis is that they are non-invasive and easy to administer. The test involves collecting a sample of saliva from the mouth using a swab.
Hair drug testing for cannabis is very reliable. Hair samples can be tested and results can be obtained for drug usage up to 90 days after the event with a high level of accuracy.
How Long Can Cannabis Be Detected in Drug Tests?
The length of time that cannabis can be detected in a drug test depends on several factors, including the type of test used, the frequency and amount of cannabis consumed, and individual metabolism.
For urine tests, occasional users may test positive for 1-5 days after last use, while heavy users could test positive for up to 30 days or more. Saliva tests generally detect cannabis use within the past 24-48 hours. However, they may occasionally show positive results up to 72 hours after last use for heavy smokers.
Hair tests have the longest detection window, with cannabis metabolites remaining detectable for up to 90 days after last use. These tests examine the oil in skin cells that make up the hair follicles. Since hair growth is slow, a 1.5 inch hair sample taken from close to the scalp can provide a window of cannabis use for the past 90 days.
It’s important to note that none of these tests indicate impairment, only past usage. The sensitivity of drug tests combined with the long elimination time of cannabis metabolites means that positive test results do not necessarily signify recent use or impairment.
Which Brands of Drug Test Kits for Cannabis Are the Most Accurate?
Zoom Testing only offers and sells drug test kits from reputable drug test manufacturers around the world. All tests are CE marked and quality assured.
Photo Credit: “Joint Stuff” (CC BY 2.0) by halseike
Zoom Testing is a leading UK drug testing company and a supplier of Drug Test Kits.
This post was originally published in October 2015. It was last checked and updated in June 2024.
