Macroprolactinémie

Macroprolactin or big-big prolactin is a high molecular mass form of prolactin (> 100 kDa). It is most frequently a complex of prolactin and IgG and has minimal bioactivity in vivo. In some individuals it may be the predominant immunoreactive component of circulating prolactin and cause an apparent hyperprolactinemia (macroprolactinemia), whereas concentration of monomeric prolactin with biological activity is normal. Macroprolactinemia can lead to diagnostic confusion and unnecessary further investigation and treatment if it is not recognized. It essential that laboratories screen for macroprolactin and estimate the concentration of bioactive monomeric prolactin. In this review, screening tests for macroprolactin are compared and a practical approach for the etiological diagnostic of hyperprolactinemia including screening for macroprolactin and monomeric prolactin estimation is presented.