Macroprolactin, in Visit Clinic

Macroprolactin is usually benign; confirm with a polyethylene glycol (PEG) precipitation test. If macroprolactin predominates and the patient is asymptomatic, no treatment is needed—monitor clinically and biochemically. Treat only if true (monomeric) hyperprolactinemia or symptoms: address underlying causes (medications, hypothyroidism), consider dopamine agonists (cabergoline or bromocriptine), and refer to endocrinology for imaging.

High prolactin (hyperprolactinemia) in females commonly causes irregular or absent menstrual periods, reduced fertility, and galactorrhea (milk discharge). It can lower estrogen, leading to vaginal dryness, decreased libido and risk of bone thinning. Large pituitary tumors may cause headaches and visual field defects. Other effects include acne or hirsutism; evaluation and treatment are recommended to restore hormones and fertility.

Macroprolactin is a large, often inactive prolactin complex that can raise total prolactin on lab tests. PEG precipitation separates it: low post‑PEG recovery (commonly <40%) indicates predominance of macroprolactin (usually clinically insignificant); high recovery (>50–60%) indicates true hyperprolactinaemia. Intermediate results (~40–60%) are uncertain. Interpret with symptoms; if symptomatic or unclear, repeat testing, use alternative assays, or refer to endocrinology.

Markedly elevated prolactin levels suggest a prolactin-secreting pituitary tumour. As a rule: levels above about 200 ng/mL are strongly suggestive of a prolactinoma; levels over ~500 ng/mL make a macroprolactinoma (larger tumour) more likely. Mild-to-moderate rises (<100–150 ng/mL) often have other causes. Diagnosis requires repeat testing, clinical assessment and pituitary MRI.

High macroprolactin usually reflects large, antibody-bound prolactin that is biologically inactive. It commonly causes raised total prolactin on lab tests but is generally not harmful and often requires no treatment if the patient has no symptoms. Laboratory confirmation (e.g., PEG precipitation) prevents unnecessary imaging or dopamine‑agonist therapy. Investigate or treat only when symptoms or elevated monomeric prolactin are present.

To lower high prolactin, see a doctor for blood tests and pituitary imaging and treat underlying causes such as hypothyroidism. Review and, if possible, stop medications that raise prolactin (some antipsychotics, metoclopramide) and consider dopamine‑agonist therapy (bromocriptine or cabergoline) under medical supervision. Reduce stress, improve sleep, avoid nipple stimulation and excess alcohol, and maintain healthy weight with follow-up monitoring.