[The glucagon test in diagnosis of secondary adrenal insufficiency after craniospinal irradiation: the feasibility of application, the features of performing the test, and its diagnostic informativity].

GT is highly informative and can be used as a first-level stimulation test for ruling out SAI in patients exposed to craniospinal irradiation performed to manage brain tumors. The cortisol level of 500 nmol/L is the best cut-off value for ruling out SAI according to the GT results. The insulin hypoglycemia test is used as the second-level supporting test in patients with positive GT results.