LETTER TO EDITOR: Macroprolactin and hyperprolactinaemia

Dear Editor, The recent report on “macroprolactin and hyperprolactinaemia” is very interesting. Jamaluddin et al. noted that 4.4 % of the patients have macroprolactin and concluded that “macroprolactin is a significant cause of misdiagnosis, unnecessary investigation, and inappropriate treatment.” Similar to many other “macro” phenomenon (macroCK, macroamylase, etc.), the macroprolactin can result in aberration laboratory results. The important concern is there are few reports on this “macro” phenomenon. In fact, the absolutely same conclusion (“verbatim”) was previously reported by Suli- man et al. It is already recommended that screening for macroprolactin should be done in cases with hyperprolactinemia. In some settings, this problem can be as high as 21% .