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Interpresting Test Results

Prolactin Interpretation

Serum prolactin is the definitive test for diagnosing hyperprolactinaemia.1

​​​​​​​Assessment of serum prolactin is usually straightforward and informs the need for further workup.1,2

< 25 µg/L  // Normal value

Normal value
• Proceed with further clinical evaluation of symptoms

25-250 µg/L  // Elevated value

Elevated value
• Refer to other laboratory results and the medical history to identify a
secondary cause of hyperprolactinemia (eg, hypothyroidism, medications)
• Imaging may be needed to identify presence of a pituitary or hypothalamic mass

> 250 µg/L // Elevated value, typically indicative of a prolactinoma

Elevated value, typically indicative of a prolactinoma
• Consider MRI scan and/or referral to a neuroendocrinologist

Other Test Results

Aside from prolactin measurement, several other laboratory tests should be conducted during the workup of a patient with suspected hyperprolactinaemia as part of the differential diagnosis and to help identify a cause of hyperprolactinaemia, if present.1,2,4


• Recommended for patients with asymptomatic hyperprolactinemia
• Macroprolactinemia is a common cause of hyperprolactinaemia; however, many commercial assays do not detect large polymeric forms of prolactin (i.e., macroprolactin)

β-hCG (ß human chorionic gonadotropin)

• Mandatory for any woman of childbearing age with amenorrhoea to identify possible pregnancy

FSH (follicle-stimulating hormone), LH (luteinizing hormone)

• In patients with hyperprolactinaemia, levels are reduced due to prolactin interference with GnRH (gonadotropin-releasing hormone) secretion, leading to hypogonadism and infertility

TSH (Thyroid stimulating hormone)

• Useful for determining primary hypothyroidism, which can cause mild hyperprolactinaemia
• Normalization of thyroid function with levothyroxine leads to hyperprolactinaemia resolution

IGF-1 (Insulin growth factor)

• Required for all patients with macroadenomas to identify possible acromegaly

Renal function tests (e.g. creatinine)

• Useful for determining kidney dysfunction, which can cause prolactin to accumulate due to decreased clearance and enhanced production

Liver function tests

• Useful for determining hepatic insufficiency, which can cause prolactin to accumulate due to decreased clearance

1.Melmed S, Casanueva FF, Hoffman AR, et al; Endocrine Society. Diagnosis and treatment of hyperprolactinemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(2):273-288.
2.Halperin Rabinovich I, Cámara Gómez R, García Mouriz M, Ollero García-Agulló D; Grupo de Trabajo de Neuroendocrinología de la SEEN. Clinical guidelines for diagnosis and treatment of prolactinoma and hyperprolactinemia. Endocrinol Nutr. 2013;60(6):308-319.
3.Majumdar A, Mangal NS. Hyperprolactinemia. J Hum Reprod Sci. 2013;6(3):168-175.
4.Vilar L, Fleseriu M, Bronstein MD. Challenges and pitfalls in the diagnosis of hyperprolactinemia. Arq Bras Endocrinol Metabol. 2014;58(1):9-22.

PP-UNP-GBR-0580. June 2022


Selecting Treatment based on Guidelines

Determine therapy based on clinical and patient factors

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Monitoring and Management

Learn how to tailor therapy based on follow-up testing​​​​​​​

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What is Hyperprolactinaemia?

See general information including pathophysiology and etiology

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Identifying Common Symptoms

Understand what signs to look for and explore two patient cases

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For UK Healthcare Professionals*

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PP-PFE-GBR-3863. November 2021



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