how long do drugs stay in your system

Urine test. Urinalysis for drug screening is fast, convenient and generally accurate, which makes this a popular type of test for employers and law enforcement agencies, especially when random testing is required.
Blood test. Blood tests take longer to develop than urine tests, but this method is very effective at detecting concentrations of alcohol and other drugs. Blood testing can determine your level of intoxication, but only for up to 24 hours after you’ve been drinking.

Breath test. Most of the alcohol you drink is processed by your liver, but as the alcohol is being metabolized, traces are eliminated in your breath and urine. Law enforcement agents can use a device called a breath analyzer to detect the level of alcohol in your breath.
Saliva test. The saliva holds traces of alcohol, hormones and other chemicals that can indicate drug use. Saliva testing is no longer as popular as blood or urine testing. Drugs can usually be detected in the saliva for only a few hours to a few days.
Hair test. Analyzing the hair for chemical traces may be the most accurate way to test for long-term drug use. Because hair grows slowly (only about 0.5 inches per month), traces of certain drugs can be detected for months. Hair analysis requires more processing time than urine or blood testing.