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 or menstrual problems.