Prolaktin

Prolactin is a hormone of the pituitary gland that stimulates milk production in the mammary glands after birth. The laboratory value measures the prolactin concentration in the blood, which can also provide information about hormonal imbalances in non-pregnant individuals or men.

A prolactin test is recommended for: • Women with irregular menstrual cycles or absence of menstruation • Women with unexplained milk production outside of pregnancy or breastfeeding (galactorrhea) • Men with loss of libido, infertility or breast enlargement (gynecomastia) • Patients with symptoms that could indicate a pituitary tumor (e.g. visual disturbances, headaches)

The test serves the diagnosis of hyperprolactinemia, which can be triggered by pituitary tumors, stress or medication. It also helps to identify the cause of fertility problems or menstrual disorders.

A high prolactin level can indicate the following conditions: • Prolactinoma (pituitary tumor) • Stress, hypothyroidism or medications (e.g. antidepressants, antipsychotics) • Milk production outside of breastfeeding (galactorrhea) A low value usually has no clinical significance.

The test should be performed in the morning and fasting, as prolactin levels can fluctuate during the course of the day and can be influenced by stress or physical activity.

• Prolactin is stress-dependent; even minor stress before the blood draw can increase the values. • An elevated prolactin value alone requires further diagnostics (e.g. MRI of the pituitary gland) to clarify the cause. • Hypothyroidism can cause hyperprolactinemia and should be excluded.