(DY-ug-NAH-stik proh-SEE-jer)

A test used to help figure out what disease or condition a person has based on their signs and symptoms. Diagnostic procedures may also be used to help plan treatment, find out how well treatment is working, and make a prognosis. There are many different types of diagnostic procedures. Examples include laboratory tests (such as blood and urine tests), imaging tests (such as mammography and CT scan), endoscopy (such as colonoscopy and bronchoscopy), and biopsy. Also called diagnostic test.