The objective of this study was to report the results of initial investigation and after 5 years of patients with a suspicious clinical scenario (1-5) and elevated IGF-1, who would have a diagnosis of acromegaly based on the nadir GH cut-off value of 0.4 μg/L (1,4,12-18) but not 1 μg/L (3,9). Here, GH1 is linked to acromegaly.