Pre-test cortisol levels in predicting short synacthen test outcome: A retrospective analysis

Ravindran, Ravikumar, Carter, Joanne L, Kumar, Asit, Capatana, Florin, Khan, Ishrat N, Adlan, Mohamed A and Premawardhana, Lakdasa D 2022. Pre-test cortisol levels in predicting short synacthen test outcome: A retrospective analysis. Clinical Medicine Insights: Endocrinology and Diabetes 15 10.1177/11795514221093316

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Abstract

Objective: Short Synacthen tests (SSTs) are expensive, dependent on Synacthen availability, and need supervision. To reduce SST testing, we examined the utility of pre-test cortisol (Cort0) and related parameters in predicting outcome. Design and Measurements: We retrospectively examined the following in all SSTs; (i) Cort0 (ii) indications (iii) and time and place of testing. Receiver operated characteristic (ROC) curves were devised for Cort0 to obtain the best cut-off for outcome prediction in those who had SSTs between 8 and 10 am (Group 1) and at other times (Group 2). Results: Of 506 SSTs, 13 were unsuitable for analysis. 111/493 SSTs (22.5%) were abnormal. (1) ROC curves predicted – (a) SST failure with 100% specificity when Cort0 was ⩽124 nmol/L (Group 1), or ⩽47 (Group 2); (b) a normal SST with 100% sensitivity when Cort0 ⩾314 nmol/L (Group 1) and ⩾323 nmol/L (Group 2). (2) There was significant correlation between Cort0 and 30-minute cortisol ( rs = 0.65-0.78, P < .001). (3) Median Cort0 was lower in those who failed SSTs compared to those who passed (147 vs 298 nmol/L respectively, P < .001). (4) SST failure was commoner in Group 1 vs 2 ( P = .001). (5) There was no difference in outcome between out-patient and inpatient SSTs. (6) SST failure was most common for ‘steroid related’ indications (39.6%, P < .001). Conclusions: This study indicates that (1) Cort0 ⩾ 323 (Group1) and ⩾314 nmol/L (Group 2) predicted a normal SST with 100% sensitivity; (2) Using these cut offs 141/493 (28.6%) tests may have been avoided; (3) supporting evidence should be considered in those with a lower pre-test predictability of failure.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Medicine
Publisher:	SAGE Publications
ISSN:	1179-5514
Date of First Compliant Deposit:	21 October 2024
Last Modified:	21 Oct 2024 14:00
URI:	https://orca.cardiff.ac.uk/id/eprint/173184

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