Endocrine Abstracts

Aim: Short Synacthen test (SST) has become increasingly accepted and widely used screening test for the assessment of the integrity of hypothalamo-pituitary-adrenal axis (HPA), however there are difference of opinion about the duration of the test and most acceptable is 30 minutes plasma cortisol level after giving 250 μg of synacthen. Therefore we have compared 30 minutes SST with 60 minutes SST for assessment of the HPA axis.

Method: Response to the 30 minutes standard SST and 60 minutes SST were measured in 173 patients. A normal response to the synacthen test was defined by using one of the following criteria (A) a peak serum cortisol of ≥550 nmol/l (B) incremental concentration of ≥200 nmol/l from base line (C) a peak serum cortisol of ≥550 nmol/l and incremental concentration of ≥200 nmol/l from base line.

Result: Number of patients failed at 30 minutes but passed at 60 min by using criteria A 46, criteria B 39 and criteria C were 38 out of 173 patients.

Conclusion: This study revealed that 30 minutes SST could give rise to false positive results indicating that 60 minutes SST is essential in order to avoid over diagnosing adrenal steroid deficiency.