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Macroprolactin

Adrenal, pituitary and other hormones · also printed as Macroprolactin screen, Macroprolactin (PEG), Prolactin post PEG, Macroprolactinaemia screen, PEG precipitation

Typical UK adult rangeExpected result: Not significant

The usual report says macroprolactin is not present, or gives the monomeric (true) prolactin value.

What this test measures

Macroprolactin is prolactin bound up in large, inactive clumps with antibody. It registers on the prolactin test but has no effect on the body, so labs check for it whenever prolactin is raised.

Why doctors request it

Run automatically by most UK labs when prolactin is above the range, to avoid unnecessary scans.

What commonly pushes it up

The presence of macroprolactin, found in a small share of the population and harmless

What commonly pushes it down

A negative result is the usual finding

Everyday reasons for a value outside the range

Low-level positives occur in the general population and are read with the clinical picture
Thresholds differ between laboratories

About the sample

No fasting needed.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.

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This is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.