What are the limitations to saliva drug testing for THC cannabis
Detecting cannabis using saliva tests can give rise to unexpected results, especially if the test sample is not collected correctly, or if the donor has eaten, drunk or otherwise removed THC residues from the mouth. Collectors need to be aware of this when interpreting results. A negative test does not indicate the drug has not been used, just that there is no residual parent THC left in the oral cavity!
How does a saliva drug test for cannabis compare to a urine drug test
Unlike urine drug testing kits, saliva Cannabis drug tests only detect parent THC compounds, (parent THC refers to the active THC drug compound, before it is metabolised by the body) so they can only give positive results where the parent drug is still in the mouth and saliva. No metabolised THC-COOH (the first and most commonly used metabolite detected by urine tests) is detected by saliva cannabis drug tests, so the extended window of detection seen with urine tests does not exist for saliva screening.
Also unlike urine tests, saliva cannabis tests can also be affected by the subsequent actions of the cannabis user. If the oral cavity is cleaned or rinsed effectively, then all the parent THC can be removed almost immediately. This makes it essential to collect the saliva sample for screening as quickly as possible after cannabis has been smoked, and without prior notice being given that the test is to be taken. The guide window for detection using saliva is between 8 and 12 hours, but this window is dependent on the oral cavity not being cleaned after smoking.
How to maximise your success with oral drug testing for Cannabis
To maximise the chances of detection, ensure the sponge swab is moved around the mouth and in front of both top and bottom teeth and into the cheeks and under the tongue. This increases the chance of trapping THC in the sample.
What are the best uses for Saliva drug test for Cannabis
Saliva drug test kits are ideal for forensic and medical screening. Roadside drug tests which show positive also indicate that THC has been smoked recently, but may miss Cannabis smoked before the mouth has been washed or rinsed. saliva tests are also relevant for workplace screening, because, again, a positive result has to be the result of resent drug use.(versus historic)