In all likeliness, it wasn't a false positive. With a saliva test, methadone can typically be detected up to 10 days after ingestion. Everyone's metabolism is different, and with prolonged heavy use,...
Many drug tests are based off the color that the urine sample becomes once a reagent is added. Often times there will only be 3-5 different outcomes, such as 1. Marijuana - Red 2. Amphetamines -...