As the hair grows, it absorbs special markers called fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG) into its structure, which remain in the hair indefinitely. These markers are only produced when there is alcohol in the bloodstream, such that the more markers there are, the more alcohol you have consumed.
When an employer requests a drug test from an employee the employee is typically instructed to go to a collection site. The employee’s urine is collected at a remote location in a specially designed secure cup, sealed with a tamper resistant tape, and sent via express delivery service to a testing laboratory to be screened for drugs (typically SAMHSA 5 panel).