A diagnosis is the identification of an illness or medical disease by examining the signs and symptoms apparent in the patient. Making an accurate diagnosis can be made through the use of imaging procedures and/or laboratory findings from blood tests. Cancer may be diagnosed after a symptom appears, like a lump or screening test result, suggests the possibility of cancer. Lab tests with blood work, imaging procedures (such as CT scans, ultrasound, and MRI), and biopsies can all be used to make an accurate cancer diagnosis. To avoid misdiagnosis and unnecessary treatment, an expert in the field who has analyzed a cell or tissue under a microscope will make the diagnosis. Learn more about cancer laboratory tests from Comprehensive Cancer Centers of Nevada.