Macroprolactin and hyperprolactinaemia.

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 Suliman 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% . Of interest, no clinical or other laboratory features have proved helpful for differentiating true hyperprolactinemia from pseudo cases due to macroprolactin. Nevertheless, the important points at present include (a) the knowledge of the general practitioner on this problem, (b) the availability of a laboratory that can test for macroprolactin and (c) the cost of the test.