When diagnosing prolactinoma, a doctor usually asks questions about a person's medical history and considers the possible symptoms a patient has. When a doctor is making a prolactinoma diagnosis, he or she will likely need to order certain tests. These tests measure the prolactin levels in the blood and test thyroid function. An MRI scan may also be ordered to determine the size and location of the pituitary tumor.
In order to make a prolactinoma diagnosis, the doctor will usually ask a number of questions about a person's medical history, including his or her current symptoms, whether there is a family history of any medical problems, and any medicines the patient is taking. The doctor will then most likely perform a physical exam, looking for any signs of a prolactinoma, and will order certain tests.
A doctor diagnosing prolactinoma will typically test for prolactin blood levels in women with unexplained milk secretion (galactorrhea) or irregular menses or infertility, and in men with impaired sexual function and, in rare cases, milk secretion. If prolactin is high, a doctor will test thyroid function and ask first about other conditions and medications known to raise prolactin secretion.
The doctor will also usually request a magnetic resonance imaging (MRI) scan, which is the most sensitive test for detecting pituitary tumors and determining their size. MRI scans may be repeated periodically to assess tumor progression and the effects of prolactinoma treatment. A computer tomography (CT) scan also gives an image of the pituitary, but it is less sensitive than the MRI.
In addition to assessing the size of the pituitary tumor, doctors also look for damage to surrounding tissues and perform tests to assess whether production of other pituitary hormones is normal. Depending on the size of the tumor, the doctor may request an eye exam with a test that measures the visual field.