UA: Abbreviation for urinalysis, a test that determines the content of the urine. Because urine removes toxins and excess liquids from the body, it can contain important clues. Urinalysis can be used to detect some types of disease, particularly in the case of metabolic disorders and kidney disease. It can also be used to uncover evidence of drug abuse. Accurate urinalysis usually requires a "clean catch" of urine. If you are giving a urine sample, drink plenty of fluids in advance, and wait until one or two seconds into the flow of urine before urinating into the receptacle. For some tests it is important to get the first urine of the day, which will contain the highest concentration of toxins and other clues.