Prolactin
Code:9017|CPT:84146|LOINC:2842-3
| Includes | Prolactin |
|---|
Analysis details
Methodology
- Electrochemiluminescence immunoassay (ECLIA)
Expected Turnaround Time
1 day
Special Instructions
- Infants younger than 1 year: avoid feeding for 30–40 minutes before the blood draw.
- Children 1–5 years: do not give food for 2–3 hours before collection.
- Older children and adults: refrain from eating for 2–3 hours before collection; water is allowed.
- If clinically acceptable, hold steroid and thyroid hormone medications for 48 hours before collection.
- Limit physical and emotional stress during the 24 hours before the test.
- Do not smoke during the 3 hours preceding collection.
- If taking high-dose biotin (>5 mg/day), collect the specimen at least 8 hours after the last dose.
How to use
The Prolactin (PRL) test, also known as lactotropic hormone or mammotropin measurement, is a first-line laboratory study for galactorrhea and menstrual disorders such as amenorrhea or anovulation. It is used to assess pituitary function when a prolactin-secreting adenoma is suspected—whether microadenoma or macroadenoma—and whether or not sellar imaging shows abnormalities. Measurement is also integral to the workup of infertility and sexual dysfunction, including male hypogonadism, and is used to monitor patients with established prolactinomas during therapy. Elevated prolactin may accompany corpus luteum insufficiency or anovulation. Chronic hyperprolactinemia can lead to amenorrhea, anovulation, and reduced bone density.
Limitations
Prolactin (PRL) secretion occurs in pulses and follows a circadian pattern, with physiologic augmentation by suckling and by stress. Concentrations rise during pregnancy and the postpartum period to support lactation, then decline after breastfeeding ceases. Prolactin-secreting pituitary adenomas are a common cause of pathological hyperprolactinemia. As these tumors enlarge, they can produce mass effects such as headache and visual impairment and may disturb secretion of other pituitary hormones, contributing to infertility in women and hypogonadism in men.
| Unit | ng/mL | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Reference interval |
| |||||||||
| Indications | Clinical features suggestive of a prolactinoma, including headaches, visual field loss, or galactorrhea, Workup of infertility or sexual dysfunction, Assessment of male hypogonadism in the context of low testosterone, Follow-up and management of a confirmed prolactinoma, Evaluation of suspected hypopituitarism in conjunction with growth hormone testing, Surveillance in patients taking medications that alter dopaminergic activity |
Possible Causes of Abnormal Results
Increased levels
- amphetamines
- anorexia nervosa
- breastfeeding
- chronic kidney disease
- dibenzodiazepines
- estrogen therapy
- hypothalamic disorders
- hypothyroidism
- methyldopa
- opiates
- phenothiazines
- pituitary neoplasms (nonprolactinoma)
- pregnancy
- reserpine
- stress
- trh administration
- tricyclic antidepressants
- verapamil
Decreased levels
- biotin (high dose)
- dopamine
- ergotamine derivatives
- levodopa
Specimen Requirements
| Specimen | Serum |
|---|---|
| Container | Gold/Tiger Top (SST, Gel Separator) |
| Volume | 1 mL (min 0.7 mL) |
| Storage Instructions | Room temperature, Refrigerated, Frozen |
References
Baskin HJ. Endocrinologic evaluation of impotence. South Med J. 1989 Apr;82(4):446-449. PubMed 2495570 Berczi I, Cosby H, Hunter T, Baragar F, McNeilly AS, Friesen HG. Decreased bioactivity of circulating prolactin in patients with rheumatoid arthritis. Br J Rheumatol. 1987 Dec;26(6):433-436. PubMed 3690137 Burrow GN, Wortzman G, Rewcastle NB, Holgate RC, Kovacs K. Microadenomas of the pituitary and abnormal sellar tomograms in an unselected autopsy series. N Engl J Med. 1981 Jan 15;304(3):156-158. PubMed 7442734 Fujimoto VY, Clifton DK, Cohen NL, Soules MR. Variability of serum prolactin and progesterone levels in normal women: The relevance of single hormone measurements in the clinical setting. Obstet Gynecol. 1990 Jul;76(1):71-78. PubMed 2359568 Kelly PA, Djiane J, Postel-Vinay MC, Edery M. The prolactin/growth hormone receptor family. Endocr Rev. 1991 Aug;12(3):235-251. PubMed 1935820 Kletzky OA, Davajan V. Hyperprolactinemia: Diagnosis and treatment. In: Mishell DR Jr, Davajan V, eds. Infertility, Contraception and Reproductive Endocrinology. 2nd ed. Oradell, NJ: Medical Economics Books;1986:275-301. Schlechte J, Dolan K, Sherman B, Chapler F, Luciano A. The natural history of untreated hyperprolactinemia: A prospective analysis. J Clin Endocrinol Metab. 1989 Feb;68(2):412-418. PubMed 2918052 Smith CR, Butler J, Hashim I, Norman MR. Serum prolactin bioactivity and immunoactivity in hyperprolactinaemic states. Ann Clin Biochem. 1990 Jan;27(Pt 1):3-8. PubMed 2310154 Tippet PD, Simon JA, Rifka SM, Falk RJ. Luteal phase hyperprolactinemia during ovulation induction with human menopausal gonadotropins: Incidence, recurrence, and effect on pregnancy rates. Obstet Gynecol. 1989 Apr;73(4):613-616. PubMed 2494621 Veldhuis JD, Evans WS, Stumpf PG. Mechanisms that subserve estradiol's induction of increased prolactin concentrations: Evidence of amplitude modulation of spontaneous prolactin secretory bursts. Am J Obstet Gynecol. 1989 Nov;161(5):1149-1158. PubMed 2589434