Clinical Trial: Determination of Method-specific Normal Cortisol and Adrenal Hormone Responses to the Short Synacthen Test

Study Status: Enrolling by invitation
Recruit Status: Unknown status
Study Type: Interventional

Official Title: Determination of Method-specific Normal Cortisol and Adrenal Hormone Responses to the Short Synacthen Test

Brief Summary:

Synacthen® is a synthetic analogue of ACTH which has been used since the 1960s to assess adrenal sufficiency. It is now well established as a first line test to investigate diseases of the hypothalamo-pituitary-adrenal axis and to assess adrenal function in patients on long-term corticosteroid therapy. Briefly, cortisol is measured before and after injection of 250 micrograms of Synacthen®. In a normal individual serum cortisol will rise to concentrations greater than an arbitrary value (typically 550 nmol/l) 30 minutes after administration of Synacthen®.

In 2004 the All Wales Clinical Biochemistry Audit group surveyed protocols for performing and interpreting short Synacthen® tests. This identified wide differences in practice within Wales. As a result standards were drawn up for performance of the test. It was noted that there was considerable variability or bias between cortisol immunoassays and that the cortisol cut-off chosen for interpretation of the short Synacthen® test should be method dependent.

Clark et al., in 1998 reported cortisol cut-offs following Synacthen® using 4 well established commercially available cortisol immunoassays. This study demonstrated considerable differences between the cortisol immunoassays used in clinical laboratories at the time. It was also apparent that there were differences in gender-related responses to Synacthen® although there was no dependence on age. In the 8 years since publication of this study there have been advances in formulation of cortisol immunoassays as well as the instrumentation used to perform analyses. At the University Hospital of Wales cortisol is currently assayed using the Bayer Centaur automated immunoassay analyser. This assay was not available at the time of the study by Clark et al.,. The investigators' current short Syn

Detailed Summary:
Sponsor: Cardiff University

Current Primary Outcome: The primary end-point of the study will be to establish method dependent cortisol cut offs for the normal response to Synacthen® using the 5th percentile. [ Time Frame: Cortisol response at 30 minutes ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Cortisol measurements by immunoassay will be compared with the GC-MS gold standard method for normal volunteers and patients with hypopituitarism and hypoadrenalism. [ Time Frame: Cortisol response at 30 minutes ]
  • Synacthen® responses in women taking ethinyloestradiol-containing contraceptive pills will be compared with those who are not. [ Time Frame: Cortisol response at 30 minutes ]
  • We will establish cut offs for the salivary cortisol response to Synacthen® in normal volunteers using the 5th percentile. [ Time Frame: Cortisol response at 30 minutes ]
  • We will establish a 17OHP cut off in response to Synacthen® in normal female volunteers using the 5th percentile. [ Time Frame: 17OHP response at 60 minutes ]


Original Secondary Outcome: Same as current

Information By: Cardiff University

Dates:
Date Received: February 25, 2009
Date Started: September 2008
Date Completion: July 2010
Last Updated: February 24, 2010
Last Verified: February 2009