Figure 2.

Diagnostic workup for hyperprolactinemia. Scarceness or absence of the peculiar clinical syndrome of PRL excess in patients with PRL levels <250 μg/L should suggest the screening for macroprolactin before performing a pituitary MRI (left). In patients with overt clinical syndrome of PRL excess and PRL values >250 μg/L, the diagnosis of a prolactinoma can be ruled in and a pituitary gadolinium-enhanced MRI is strongly recommended (right), to investigate for the presence of a microadenoma or a macroadenoma. Discrepancy between PRL levels and tumor size, particularly in case of tumor size > 3 cm, should suggest a potential hook effect and requires the reassessment of the sample with serum dilution (at least 1:100, middle). Created with Biorender.com.