Endocrine Abstracts

Current trust protocol for the Short Synacthen Test (SST) is to perform cortisol levels at 0, 30 min and 60 min; there is a variation in this policy in different trusts. This quality improvement project determined if the 60 min test was significant and, if so, in what proportion of patients. A further aspect of the audit was in regards to determining if the number of SSTs in the trust could be reduced. We investigated every adult having a SST run through the SWFT laboratory during the period 05/12/14 to 05/12/15; giving us a sample of 121 tests. There was a strong positive correlation between baseline cortisol and 30 min cortisol. 95 tests classed as passed at 30 min. Of these, 30 had a baseline cortisol level >550 nmol/l. Eight tests did not reach 550 nmol/l at 30 min, but did at 60 min; the majority of patients in this group had known hypothalamic- pituitary- adrenal disease and the remainder were elderly patients who had been admitted acutely unwell. We reviewed the literature and discussed the lack of consensus on timing of cortisol levels. We advised that removal of the 60 min test would be associated with a risk of falsely labelling 7% of the tests as adrenally insufficient and that those with known HPA axis disease should be considered for 30 and 60 min cortisol levels. We reviewed the literature regarding early morning cortisol levels as measure to predict adrenal sufficiency. We calculated that setting a threshold for early morning cortisol at 425 nmol/l would have a sensitivity of 100% and a specificity of 56.25% for identifying those with adrenal insufficiency from our sample. If this threshold was used then 54 (45%) SSTs could have been avoided, with a potential cost saving of £2700 annually.