Wiktionary
n. Any chemical check for the presence of (usually illegal) drugs in a sample of one's blood, hair or urine.
Wikipedia
A drug test is a technical analysis of a biological specimen, for example urine, hair, blood, breath, sweat, or oral fluid/saliva—to determine the presence or absence of specified parent drugs or their metabolites. Major applications of drug testing include detection of the presence of performance enhancing steroids in sport, employers screening for drugs prohibited by law (such as cannabis, cocaine and heroin) and police officers testing for the presence and concentration of alcohol (ethanol) in the blood commonly referred to as BAC (blood alcohol content). BAC tests are typically administered via a breathalyzer while urinalysis is used for the vast majority of drug testing in sports and the workplace.
Usage examples of "drug test".
In fact, the governor's urine screen for drivers is not a drug test so much as an intelligence test.
It had taken months to put an end to the newspaper reports, even after she had taken a voluntary drug test in an effort to end the speculation.
A student who flunked a drug test found his quarters searched at once, all legal and proper, as there were seven judges in town willing night and day to issue search warrants on 'probable cause'.