People in charge of drug testing must assume that there is some degree of cheating therefore some effective security measures must be implemented in their programs to prevent and detect adulteration. © Copyright Expomed 1995-2019

Three common methods of tampering are:

• External (in vitro). Substances added to the urine sample after voiding.
• Internal (in vivo). Things ingested to disguise the drugs in their systems.
• Substitution. Substitution of clean urine.