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Should macroprolactin be measured in all hyperprolactinaemic sera?
1Department of Endocrinology and Diabetes Mellitus, Saint Vincent's University Hospital, Elm Park, Dublin 4, Dublin, Ireland. mckennatj@gmail.com
Clinical Endocrinology
|March 27, 2009
Summary
Macroprolactin, a large prolactin variant, causes most cases of hyperprolactinaemia. Recognizing macroprolactinaemia prevents unnecessary tests and misdiagnosis.
Area of Science:
- Clinical Biochemistry
- Endocrinology
- Reproductive Medicine
Background:
- Macroprolactin is a nonbioactive prolactin isoform comprising prolactin and IgG.
- Macroprolactinaemia accounts for approximately 10% of clinical hyperprolactinaemia cases in the UK and US.
- Failure to identify macroprolactinaemia leads to unnecessary investigations and inappropriate treatment.
Purpose of the Study:
- To highlight the clinical significance of macroprolactinaemia.
- To advocate for routine screening of hyperprolactinaemic sera for macroprolactin.
- To emphasize the cost-effectiveness and availability of screening methods.
Main Methods:
- Polyethylene glycol (PEG) precipitation assay is the primary method.
- PEG precipitates high-molecular-weight constituents, including macroprolactin.
- Re-assaying prolactin levels after PEG treatment identifies macroprolactinaemia.
Main Results:
- Macroprolactin is a common cause of elevated prolactin levels.
- Screening readily identifies macroprolactinaemia in biochemistry laboratories.
- The PEG precipitation method effectively distinguishes macroprolactin from bioactive prolactin.
Conclusions:
- Routine screening for macroprolactin in hyperprolactinaemic patients is strongly recommended.
- Early recognition of macroprolactinaemia improves diagnostic accuracy and patient management.
- Available screening methods are effective, accessible, and cost-efficient.
