Macroprolactin

Macroprolactin is a physiologically inactive form of prolactin found in a small proportion of people. It is in fact prolactin bound to IgG.

Macroprolactin is important, as some laboratory assays will detect it as prolactin, leading to a falsely elevated prolactin result. This can lead to a misdiagnosis of hyperprolactinaemia in some people, especially those with other symptoms, such as infertility^[1] or menstrual problems.

There are certain chemicals, such as polyethylene glycol, that can be added to remove macroprolactin from a suspicious sample. The sample can then be re-analysed to see if the prolactin levels are still high.

Gold standard test to diagnose macroprolactin is gel-filtration chromatography.

Literature

• Sadideen H, Swaminathan R. (2006): "Macroprolactin: what is it and what is its importance?" Int J Clin Pract. 60(4):457-61.

References