How does cannabis THC saliva test work?

When you smoke, THC (Δ9-tetrahydrocannabinol) is first deposited in your mouth. This is the raw molecule found in marijuana and cannabis seeds. Once inhaled, the molecule is transformed by the body, which metabolizes cannabidiol. This is called the metabolite THC-COOH (11-nor-9-carboxy-Δ 9-tetrahydrocannabinol).

How does it work in practice? The tester applies a stick, for about two minutes, between your gum and your cheek. This saliva test only detects THC. If you smoke a joint occasionally, your chances of getting caught are slim, as it takes about three days for the THC in your saliva to be removed.
The urine test allows for a deeper screening. It detects cannabis use over several weeks by looking for the presence of THC-COOH.

Studies and the testimony of some users show that saliva tests are not 100% reliable. This is probably one of the reasons why the detection threshold is not defined by legislation. In fact, the limits of science are accepted by the courts and only a blood or urine test is admissible.

Saliva tests do not only detect cannabinoids, but also other narcotics such as amphetamines, cocaine and opiates. This means that a person who has just taken a codeine paracetamol can test positive.

It is strongly discouraged to refuse a saliva test as you could be fined, lose 6 points on your license and go to jail.
If you have a test planned, the only foolproof method is to quit smoking! Be aware that the CBD is non-psychoactive in nature. Its THC content is very low – less than 0.3% – so you are unlikely to test positive.
If you don’t want to quit smoking or during an unannounced test, it is possible, according to some users, to counteract the saliva test. No method is 100% certain, but you can test a few tips at home and draw your own conclusions.
Fat cells would participate in the absorption and storage of the THC molecule. Enjoy a meal with high fat foods and observe the result.
Good dental hygiene is important. Brush your teeth several times a day for several minutes, paying special attention to the gums and tongue. You can also make a mouthwash by mixing lemon juice, vinegar or hydrogen peroxide. Your saliva will dilute a little, which can minimize the THC content.
Ready-to-use products are also available on the market that can mask the presence of THC for 30 minutes.