Description
Prolactin level tests may be ordered when a patient has symptoms such as: unexplained headaches, visual impairment, and/or galactorrhea.
They can also be ordered, along with other tests, when a woman is experiencing infertility or irregular menses; or when a man has symptoms such as: a decreased sex drive, galactorrhea, or infertility. Prolactin levels are also often ordered in men as a follow-up to a low testosterone level.
When a patient has a prolactinoma, prolactin levels may be ordered to monitor the progress of the tumor and its response to the treatment. They may also be used at regular intervals to monitor for recurrence.
Prolactin levels may be ordered, along with other hormone levels such as growth hormone, when doctor suspects that a more general hypopituitarism (low levels of pituitary function that result in lowered levels of thyroid or adrenal hormones) exist.
Its concentration is measured by means of analysis of a blood sample drawn from the vein in the arm.
Purpose of the test
Prolactin levels are used, along with other tests, to help:
- Determine the cause of galactorrhea
- Determine the cause of headaches and visual disturbances
- Diagnose infertility and erectile dysfunction in males
- Diagnose infertility in females
- Diagnose prolactinomas
- Evaluate anterior pituitary function (along with other hormones)
- Monitor treatment of prolactinomas and detect recurrences
Reference range values
Male
2.1-17.7 ng/mL
Female
1-9 years: 2.1-17.7 ng/mL
10 years and older: 2.8-26.0 ng/mL
Abnormal findings
Prolactin levels will vary over a 24-hour period, rising during sleep and peaking in the morning.
High Levels:
High levels of prolactin (hyperprolactinemia) are normal during pregnancy and after childbirth while nursing.
High levels are also seen with:
- Anorexia nervosa
- Drugs: Estrogen, tricyclic antidepressants, and drugs that block the effect of dopamine such as: tranquilizers, some hypertension drugs, and some drugs that are used to treat gastroesophageal reflux
- Hypothalamic diseases
- Hypothyroidism
- Kidney disease
- Nipple stimulation
- Other pituitary tumors and diseases
- Polycystic ovary syndrome
- Prolactinomas
Low levels:
Levels of prolactin that are below normal are not usually treated but may be indicative of a more general hypopituitarism.
Low levels may also be caused by drugs such as: dopamine, levodopa, and ergot alkaloid derivatives.