Diagnosis and differential diagnosis of
Cushing's syndrome remains a challenge in clinical endocrinology. The aim of this study was to establish the value of assessing
adrenocorticotropic hormone (
ACTH) levels in differential diagnosis of
hypercorticism using receiver operating characteristic (ROC) curve. We have evaluated 114 patients with
Cushing's syndrome testing the value of pathohistological examination and postoperative testing. The control group consisted of 53 obese healthy persons.
ACTH level was determined using a commercial RIA (CIS, France).
ACTH secreting pituitary adenoma was found in 56.14% examinees, ectopic secretion in 6.14%,
cortisol secreting adrenal
adenoma in 37.57%, and adrenal
carcinoma in 6.14% of all patients with
Cushing's syndrome. Basal
ACTH level for
pituitary adenoma was 107.29 +/- 75.69 pg/mL; for ectopic secretion 181.63 +/- 149.84 pg/mL; for adrenal
adenoma 4.22 +/- 2.32 pg/mL; for adrenal
carcinoma 5.50 +/- 7.72 pg/mL; and 34.76 = 10.07 pg/mL in control group. Testing the value of assessing
ACTH the area under ROC curve was 0.9965 +/- 0.0071. Test sensitivity was 99.89% and test specificity was 97%. For
ACTH cut-off level of 8 pg/mL, test sensitivity was 88.50%, with specificity of 99%. For
ACTH cut-off level of 22 pg/mL, test sensitivity was 99.30%, with specificity of 98%. Our intermediate zone from 8 to 22 pg/mL confirms that assessment of
ACTH level is a reliable tool in differential diagnosis of
Cushing's syndrome.