How far back can cotton swab tests detect marijuana?

Cotton swab tests, also known as oral fluid tests, are used to detect recent drug use. They can typically detect marijuana use within the past 1-3 days. However, the specific detection window can vary depending on factors such as the frequency and amount of marijuana use, the individual's metabolism, and the sensitivity of the test.

In general, saliva drug tests are less sensitive than urine or blood tests and may not be able to detect marijuana use that occurred more than a few days ago. Therefore, a negative result on a saliva drug test does not necessarily mean that someone has not used marijuana in the past. If recent marijuana use is suspected, a more sensitive urine or blood test may be used to confirm the result.