Endocrine Abstracts

Back ground: Our Cortisol assay was changed from older generation assay to new second-generation Roche cortisol assay for the Short synacthen tests. There is ~ 20–25% difference in cortisol values between these assays. There are debates about the cut off values for normal response (cortisol of 420 or 440 nmols), compared to 550 nmols/l with older assay. And to assess the use of 30 and 60 min cortisol response.

Methods: Short synacthen tests data were collected from hospital database. 114 short synacthen tests were performed in our hospital between August 2016 to July 2017.

Results: Out of the 114 patients, 63(55%) were females and 51(45%) were males. Age range varied from 1 to 89 years. If 440 nmols/l is used as normal response, 19/114 patients failed to reach this level at 30 min sample, but 3/19 reached the 440 nmols at 60 mins. 16/114 patient’s results were in the inadequate response range. Three patients who, did not reach the target at 30 min but reached target at 60min, were on some form of steroid treatment. (2 were on long term steroids, and one patient has had depo steroid injection). If 420 nmols/l is used as normal response, 17/114 failed to reach this level at 30 min, 2/17 of these patients reached 420 nmol level at 60 min. one patient was on long term steroids, another had steroid injection. One patients who has been confirmed to have Addison’s disease with positive adrenal antibody, would have been missed if the 420 nmol/l is used as the normal response.

Discussion and conclusion: We recommend using 440 nmols/l as normal response for SST. Also changed protocol to use only 30 min response. We are hoping to increase the capacity to do more tests, by reducing the cost of these tests by 33% and reducing the Endocrine nurses time by 50%.