High levels of
prolactin (usually higher than 200 ng/mL) may mean a pituitary gland tumor (prolactinoma) is present. The higher the prolactin level, the more likely a pituitary gland tumor is present. If a prolactin level is over 200 ng/mL, a MRI test may be done to confirm a pituitary tumor is present. A normal or low prolactin level does not always mean there is no pituitary tumor. An MRI may be done if a pituitary tumor is suspected.
High levels of prolactin may mean that the pituitary gland is making excess prolactin for unknown reasons (idiopathic hyperprolactinemia).
Other conditions that can cause high prolactin levels include pregnancy,
liver disease (cirrhosis),
kidney disease, and hypothyroidism.
Many conditions can affect prolactin levels. Your doctor will talk with you about any abnormal results in relation to your symptoms and past health.