Urinalysis has long been a tool of medical labs to detect kidney problems and other body diseases or malfunctions. More recently, it is being used to detect the presence of Alzheimer's disease. It is now widely used for the testing of alcohol and drugs, which can be detected for several days to weeks after use, depending upon the type, frequency, and amount. One of the original methods of avoiding detection was to make a mixture of fake urine, which would be poured, from a container into the specimen cup by the user. Others would save clean urine from when they were not using, for use later. Testing labs caught on to this trick and started asking clients to empty their pockets and leave their purses outside of the lavatory when they went in to give their specimen. Along came a contraption called the "Whizzinator" that is tied to the leg or waist underneath clothing. It contains a small pouch into which clean or fake urine is poured for later retrieval in the restroom.

Labs know what the temperature of a fresh urine sample should be and they also know that a sample should have blood particles in it of the blood type of the person being tested; so it is riskier to try and evade the urinalysis test by using a urine substitution. Labs take the specimen and either mix it with chemicals or dip a chemical colored test strip into it; or in some cases they examine it more closely in lab testing devices, depending on the type of substance they are looking for. This test is now usually used for random job tests, or when an employer feels he has cause to test you, because they can get a faster answer.