Comparative evaluation of 30 and 60 minutes cortisol Levels During Short Synacthen Test for diagnosis of Adrenal Insufficiency

Abstract

To assess and compare diagnostic value of 30-minute cortisol level over 60-minute level in the diagnosis of adrenal insufficiency.The comparative cross-sectional study was conducted at the Armed Forces Institute of Pathology, Rawalpindi, Pakistan, from August 2017 to May 2018, and comprised patients referred to the facility for short synacthen test with suspicion of adrenal insufficiency. Blood samples for serum cortisol were taken at time-0 and then 30 and 60 minutes after the adreno-cortico-tropic hormone injection. Total serum cortisol was measured. Adrenal insufficiency was defined as stimulated cortisol level <500 nmol/l at 30 and 60 minutes post-stimulation. SPSS 24 was used for data analysis.Of the 111 subjects, 56(50.4%) were males and 55(49.5%) were females. Overall mean age was 34±20 years. Mean basal serum cortisol level was 110±98 nmol/l in patients with adrenal insufficiency and it was 294±164 nmol/l in patients with intact adrenal functions. Cortisol level at both 30 and 60 minutes was significant (p<0.001). Receiver Operating Characteristics curve was plotted which showed area under curve of 0.83 and 0.82 for 60 and 30 minutes respectively.The 30-minute cortisol level post-stimulation carried no diagnostic value . Measuring cortisol level once at 60-minute post-stimulation would be of more value apart from being cost-effective in the diagnosis of adrenal insufficiency.