How to diagnose Prolactinoma ?
A doctor will test for prolactin blood levels in women with unexplained milk secretion, called galactorrhea, or with irregular menses or infertility and in men with impaired sexual function and, in rare cases, milk secretion. If prolactin levels are high, a doctor will test thyroid function and ask first about other conditions and medications known to raise prolactin secretion. The doctor may also request magnetic resonance imaging (MRI), 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 therapy. Computerized tomography (CT) scan also gives an image of the pituitary but is less precise than the MRI.
                
The doctor will 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 measurement of visual fields.