Several tests may be used to diagnose pituitary tumors, including:

• Physical exam and history 
• Blood tests and assays These tests measure the levels of hormones that are produced by the pituitary or  affected by it.
• Neurologic exam The doctor checks for alertness, muscle strength, coordination, reflexes and response to pain. The doctor also examines the eyes to look for swelling caused by a tumor pressing on the nerve that connects the eye and brain.
• CT or CAT (computerized axial tomography) scan This procedure uses a computer connected to an X-ray machine to obtain detailed pictures of areas inside the body. A dye may be used to help visualize organs or tissues more clearly.
• Echocardiogram This test uses sound waves to create a moving picture of the heart and major blood vessels.
• MRI (magnetic resonance imaging) MRI creates a series of detailed pictures of areas inside the body, using the combination of a powerful magnet, radio waves and computer imaging.
• Biopsy Tissue samples are examined under the microscope to determine what types of cells are present.