Endocrine Abstracts

Background: Short Synacthen tests (SSTs) are used to assess adrenal function by injecting tetracosactide and measuring blood cortisol after 30 and 60 min. Accuracy of timing helps enable successful interpretation of results. A SST is an invasive test although it is normally well tolerated. There is an increasing cost-implication for undertaking SSTs exacerbated by recent problems with Synacthen supply.

Method: We undertook a retrospective audit of 333 patients over 5 years that underwent SSTs at Royal Bournemouth Hospital. We assessed for accuracy of sample timing allowing a 10 min ‘sample window’ for both samples, i.e. between 25 and 35 min after injection for the first sample and between 55 and 65 min after injection for second sample.

Results: Two tests were excluded from analysis as no sample timing was recorded. 57% (190/331) of SSTs were performed incorrectly with poor sample timing. 46% (151/331) of first samples were outside of the ‘sample window’ with most of the samples being taken late (median time to test 35 min, range 13–197). There was no second sample in 17% (57/331) of tests. If the first sample was taken late the 30 min gap between the two samples was maintained in the majority of cases leading to delayed second sampling. 47% (129/274) were outside of the second ‘sample window’ again with the majority being taken late (median time to test 65 min, range 30–198).

Discussion: The majority of SSTs done at RBH are performed incorrectly and this has an impact on the interpretation of these tests. Approximately £2000 was spent analysing cortisol levels and injecting Synacthen in these tests. Discussing all future SSTs with the endocrine team could improve performance and reduce cost.