Even though Endocrine Society guidelines point out that with more sensitive new assays used for GH determination, a nadir of GH serum < 0.4 ng/mL after an orally administered glucose load could be used to exclude acromegaly, they suggest that it is sufficient to use the cut-off value < 1 ng/mL after an orally administered glucose load to exclude this disease. Here, GH1 is linked to acromegaly.