Hyperprolactinemia and Macroprolactinemia

Hyperprolactinemia due to big big prolactin is differently detected by commercially available immunoassays.
-B Cavaco, S Prazeres, et al.
J Endocrinol Invest. 1999 Mar;22(3):203-8.

"Macroprolactinemia, i.e. sustained hyperprolactinemia where the predominant circulating form of prolactin (PRL) is of large molecular weight, is a common phenomenon comprising up to one-fourth of all cases of hyperprolactinemia."

"we suggest that the routine measurement of PRL should be done with methods that are only minimally affected by the presence of macroprolactin."