The Role of Low-dose ACTH Stimulation Test in the Diagnosis of Adrenal Insufficiency / 대한내분비학회지

ABSTRACT

BACKGROUND: Rapid adrenocorticotropin (ACTH) stimulation test using 250ug of ACTH (1-24) has been used as a standard test in the initial assessment of adrenal function. However, it has recently been suggested that a rnaximal cortisol response can be achieved with a much lower ACTH dose, and reducing the dose might further enhance the sensitivity of the test in the detection of mild adrenal insufficiency. This study was performed to evaluate the role of low-dose (lug) ACTH stimulation test in the assessment of adrenal function and the diagnosis of subtle adrenal insufficiency. METHODS: Twenty-two subjects with suspected adrenal insufficiency due to long-term corticosteroid use were included in this study. The correlations between clinical features and the serum cortisol responses to low dose (lug) and high dose (250 ug) ACTH stimulation were evaluated. RESULTS: In high dose test, 10 (67%) out of 15 subjects with clinical features of adrenal insufficiency showed decreased serum cortisol response (peak cortisol level 18ug/dL). On the other hand, 14 (93%) subjects with clinical features of adrenal insufficiency showed decreased serum cortisol response in low dose test, while only one showed normal response. In 7 subjects without clinical features of adrenal insufficiency, 5 subject (71%) showed normal response, and 2 subjects (29%) showed decreased response in both low and high dose tests. CONCLUSION: These results suggest that the 1-ug low dose ACTH stimulation test might be more sensitive than conventional 250-ug test in the detection of mild adrenal insufficiency. Further studies are needed to determine the optimal dose of ACTH and the criteria for normal response to ACTH stimulation.