Abstract
Background: The clinical practice shows that many low-dose ACTH-stimulation tests have a false positive result. The aim of the study was to determine the diagnostic accuracy of a low-dose ACTH-stimulation test in the diagnosis of adrenal insufficiency and to define its optimal cut-off. Methods: We analyzed data from 103 patients undergoing 1 µg ACTH-stimulation test. Four patients had adrenal insufficiency (AI) upon follow up: Two primary, and two secondary AI. Cortisol serum levels were evaluated at time 0, 20’, and 30’ after the injection of 1 µg i.v. of ACTH. The sensitivity, specificity, accuracy, and positive and negative predictive values of the test were calculated for both 20’ and 30’ sampling. The receiver operating characteristic (ROC) curve was obtained to assess the sensitivity and specificity of low-dose ACTH-stimulation test in the diagnosis of adrenal insufficiency at different cut-off values. Results: Considering 500 nmol/L as the standard cut-off value, low-dose ACTH stimulation test showed a 100% sensitivity and a 67.3% specificity, with a high rate of false positive results. ROC curve analysis showed that the cut-off of 401.5 nmol/L is the best compromise between sensitivity (100%) and specificity (93.9%). Conclusions: By using a cut-off value of 401.5 nmol/L for the low-dose ACTH stimulation test, the number of false positive patients decreased significantly, but the sensitivity remained high.
Highlights
Adrenal insufficiency (AI) is a rare, life-threatening disease caused by either primary adrenal failure [1] or by hypothalamic–pituitary impairment of the corticotropic axis alone or in combination with other anteropituitary hormone deficiencies (CPHD) [2]
Of the remaining 102 patients, 66 patients showed a normal response to ACTH stimulation, with peak cortisol levels greater than 500 nmol/L (18 μg/dL)
Four patients in the Group B were diagnosed for adrenal insufficiency (AI): a female patient with hypopituitarism caused by previous pituitary macroadenoma that had been surgically-removed, a male patient with thalassemia, hypogonadism and GH deficiency, and two female patients with presumed autoimmune adrenalitis
Summary
Adrenal insufficiency (AI) is a rare, life-threatening disease caused by either primary adrenal failure [1] or by hypothalamic–pituitary impairment of the corticotropic axis alone or in combination with other anteropituitary hormone deficiencies (CPHD) [2]. The most validated test for the integrity of the hypothalamic–pituitary–adrenal (HPA) axis was the cortisol response to insulin-induced hypoglicaemia, known as the insulin stress test (IST). The clinical practice shows that many low-dose ACTH-stimulation tests have a false positive result. The receiver operating characteristic (ROC) curve was obtained to assess the sensitivity and specificity of low-dose ACTH-stimulation test in the diagnosis of adrenal insufficiency at different cut-off values. Results: Considering 500 nmol/L as the standard cut-off value, low-dose ACTH stimulation test showed a 100% sensitivity and a 67.3% specificity, with a high rate of false positive results. Conclusions: By using a cut-off value of 401.5 nmol/L for the low-dose ACTH stimulation test, the number of false positive patients decreased significantly, but the sensitivity remained high
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
