[Macroprolactin as etiology of hyperprolactinemia. Method for detection and clinical characterization of the entity in 39 patients]
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Updated: Aug 11, 2026
Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging
Published on: December 30, 2016
L García Menéndez1, A Díez Hernández, C Ciriza de los Ríos
1Servicio de Análisis Clínicos, Hospital del Bierzo, León. lgarcia@hbrz.sacyl.es
Abstract:
The presence of serum macroprolactin is a relatively frequent situation that can lead to expensive explorations and ineffective treatments. The precipitation with polyethylene glycols permits its detection rapidly, trustworthily, and inexpensively. The objective of the present work has been to assess the incidence of macroprolactin in patients with hyperprolactinemia through its identification with polyethylene glycols, as well as the clinical and radiological findings, and the response in these patients to the treatment. For it the clinical history of all the cases in which there was detected macroprolactinemia, some of them with several years of previous follow-up, was reviewed exhaustively. Of the 1505 patients in which prolactin level was determined, 195 (13%) showed values higher than 40 microg/l. In 39 (20%) of them the presence of macroprolactin was detected. After observing the evolution of these patients, spontaneously or under treatment with dopaminergic agonists, a clear relationship of causality between the presence of macroprolactin and the clinical manifestations was not found, except in a case of galactorrhea. In 27 cases nuclear magnetic resonance was done; in 4 of them a picture was observed compatible with small microadenoma or microcyst and in no patient a macroadenoma was detected. We conclude that the macroprolactinemia is a relatively frequent and easily detected entity through precipitation with polyethylene glycols. It has a limited relation with the clinical findings and there should always be sought other possible causes of this situation. It is an apparently benign situation and its identification can avoid unnecessary explorations and treatments.
Insights
Macroprolactin, a common cause of elevated prolactin, is easily detected using polyethylene glycol precipitation. Identifying macroprolactin can prevent unnecessary tests and treatments for hyperprolactinemia.
Area of Science:
- Endocrinology
- Clinical Chemistry
Background:
- Macroprolactinemia is a frequent clinical finding.
- It can lead to extensive diagnostic workups and ineffective treatments.
- Polyethylene glycol (PEG) precipitation offers a reliable method for macroprolactin detection.
Purpose of the Study:
- To determine the incidence of macroprolactin in patients with hyperprolactinemia.
- To evaluate the clinical and radiological findings associated with macroprolactinemia.
- To assess the response to treatment in patients with macroprolactinemia.
Main Methods:
- Retrospective review of clinical histories of patients with detected macroprolactinemia.
- Identification of macroprolactin using polyethylene glycol precipitation.
- Analysis of clinical manifestations, radiological findings (MRI), and treatment responses.
Main Results:
- Out of 1505 patients, 13% had elevated prolactin (>40 microg/l).
- Macroprolactin was detected in 20% of these patients (39 cases).
- A causal link between macroprolactin and clinical symptoms was not established, except for one case of galactorrhea. MRI revealed microadenomas or microcysts in 4 patients, but no macroadenomas.
Conclusions:
- Macroprolactinemia is a common and easily detectable condition.
- Its association with clinical symptoms is limited, suggesting other causes should be investigated.
- Identifying macroprolactinemia can prevent unnecessary investigations and treatments, as it appears to be a benign condition.
