Hyperprolactinaemia and Prolactinoma

Pregnancy. Puerperium. Breast stimulation. Stress physical (including excessive exercise) or psychological including venepuncture. Macroprolactinaemia: This refers to prolactin of high molecular mass, mostly complexes of monomeric prolactin with immunoglobulins (prolactin autoantibody complexes). These larger molecules have low bioactivity and a prolonged clearance rate similar to that of immunoglobulins. Depending on the immunoassay used, macroprolactinaemia may account for 25% of laboratory documented hyperprolactinaemia. Consider this cause in an asymptomatic patient with hyperprolactinaemia and consult laboratory staff (see 'Investigations', below).