A saliva test can detect traces of alcohol in the body for as long as 12 days after the consumption of alcohol, states Addict-Help. This type of test is also called an ethyl gluconoride test.
Ethyl gluconoride, or EtG tests, are most often used during the first 80 hours after alcohol consumption. A saliva test can detect alcohol use after most other types of tests, such as a breathalyzer, can no longer pick up traces of alcohol in the body. In addition to alcohol use, a saliva test can also be used to detect the use of other drugs, such as cannabis, cocaine and opiates, notes the Drug Foundation.