A medical diagnosis (an. Greek δια-γνωστικος — able to recognize) is when a doctor finds out what is making someone sick. Sometimes doctors can diagnose a sickness by asking the person questions and looking at the person's body. Sometimes doctors do "tests". Tests can mean taking a small bit of blood, urine, or tissue which is sent to a hospital laboratory where it is tested. X-rays are another form of test. Tests are ways to see how the body is working.