Prolactinoma - Diagnosis

Authored by Dr Colin Tidy, 12 May 2017

Patient is a certified member of
The Information Standard

Reviewed by:
Dr John Cox, 12 May 2017

The diagnosis may be suspected from the symptoms. Women tend to be diagnosed earlier than men because a change in the woman's periods is an early symptom and is easily noticed. Some prolactinomas are diagnosed by chance if you have tests for another reason. If a prolactinoma is suspected, you may be offered several tests.

Blood tests

A blood sample to check the level of prolactin in the blood. A very high prolactin level usually means that a prolactinoma is present. However, there are other causes of raised prolactin levels. For example, some medicines may cause high prolactin levels. These include:

Other blood tests may be done at the same time. It is important to test the thyroid gland and to check kidney function, as both these can affect prolactin levels. Further tests may be needed to see if the tumour is causing a lack of other hormones made by the pituitary gland.

Eye tests

Eye tests will assess if the tumour is pressing on the optic nerve - this includes a test of visual fields.


A magnetic resonance imaging (MRI) scan or a computed tomography (CT) scan can show the size of the tumour. A bone density scan may be advised for some patients, to check whether they are at risk of 'thinning' of the bones (osteoporosis), which is a possible complication.

Further reading and references

I was originally diagnosed last May with Prolactinoma that stemmed from not getting my period for over 6 months with off and on again headaches.  My prolactin level at that time was 200ng.  ...

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