When testing for a DUI, Drugs , various methods are employed to determine the presence and influence of drugs. These include blood tests, urine tests, and saliva tests. Blood tests are considered the most accurate and can detect a wide range of drugs, but they require a qualified medical professional to administer. Urine tests are commonly used and can detect drug use within a certain timeframe. Saliva tests are less invasive and can detect recent drug use. Additionally, field sobriety tests may be conducted to assess impairment.