What is the need for a study?

The test is performed to assess whether prolactin levels are elevated (or, less commonly, decreased). Prolactin testing is needed to diagnose a tumour of the pituitary gland called prolactinoma, and after a diagnosis of prolactinoma, to monitor the treatment of the disease and to assess whether the treatment is effective. The study is also needed to find out the cause of infertility in men and women. In the event of elevated prolactin levels, additional laboratory tests may be carried out to make sure that the increase in prolactin levels is not caused by macroprolactin.

When should I be tested?

The test is performed when there are symptoms of elevated prolactin levels, such as galactorrhoea and/or visual disturbances (blurred vision) and unexplained headaches. Elevated prolactin levels (hyperprolactinaemia) can interfere with ovarian or testicular function, so prolactin is tested for infertility, altered libido, milk production unrelated to pregnancy or childbirth, erectile dysfunction, irregular menstrual cycles, and decreased bone mineral density, along with other tests. In pituitary adenoma, prolactin is tested to monitor the tumour’s progress and response to treatment. Prolactin levels are then measured at regular intervals to assess whether the adenoma has recurred.

What sample is needed for the test?

Blood is drawn from a vein in the arm.

How to prepare for the survey?

No need. However, it should be remembered that blood should not be taken for the test until 3-4 hours after waking up.

What do my results mean?

Decreased prolactin levels are rarely detected in women after childbirth, leading to impaired milk production after pregnancy. Pregnant women tend to have higher levels of prolactin in their blood, so other reference biological values (“norms”) are used. In non-pregnant women and men, elevated prolactin levels in the blood (hyperprolactinaemia) can be a sign of a tumour of the pituitary gland (prolactinoma). However, hyperprolactinaemia can be caused by other health problems, such as kidney failure, thyroid disease and damage to areas of the brain (such as the hypothalamus and pituitary gland). A moderate increase in prolactin levels can be caused by stress related to illness, trauma or even fear of having blood drawn. The prolactin test alone does not answer the question of the cause of hyperprolactinaemia, which requires additional laboratory and instrumental tests. For example, an MRI scan of the head may be needed to confirm/reject prolactinoma. Some healthy people have elevated levels of prolactin because the hormone circulates in their blood in the form of macroprolactin (prolactin complexes). Macroprolactin is not secreted from the pituitary gland, is not biologically active and does not indicate disease. Therefore, in the case of elevated prolactin levels, additional tests are needed to determine the presence/absence of macroprolactin.

Related studies

Macroprolactin, TTH, testosterone in men, FSH, LH, urine, creatinine, electrolytes (potassium sodium, chloride), growth hormone (somatotropin).

Related conditions/diseases.

Hypothyroidism, renal insufficiency, polycystic ovary syndrome, anorexia nervosa, drug use.

You can consult our family doctors.

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