Drug test Drug test A drug test is a technical analysis of a biological specimen, for example urine, hair, blood, breath, sweat, and/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 and parole/probation officers screening for drugs prohibited by law (such as cannabis, cocaine, methamphetamine, 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
Drug tolerance of intoxication when drinking even very small amounts of alcohol. Drug tolerance should not be confused with drug tolerability, which refers to the degree to which overt adverse effects of a drug can be tolerated by a patient. Tachyphylaxis is a subcategory of drug tolerance referring to cases of sudden, short-term onset of tolerance following the administration of a drug. Pharmacodynamic tolerance begins when the cellular response to a substance is reduced with repeated use. A common cause of pharmacodynamic tolerance is high concentrations of a substance constantly binding with the receptor, desensitizing it through constant interaction. Other possibilities include