Determination of Method-specific Normal Cortisol and Adrenal Hormone Responses to the Short Synacthen Test
Status:
Completed
Trial end date:
2013-01-31
Target enrollment:
Participant gender:
Summary
Objectives:
To establish valid serum total cortisol and salivary cut-offs for use with the short
Synacthen test in patients with normal CBG concentrations.
To investigate, using current assays, the effect of assay differences on the serum total
cortisol cut-off.
To explore the performance of these cut-offs in groups of patients with suspected adrenal
insufficiency and high and low serum CBG concentration.
Methodology: An ACTH test (250 micrograms iv ACTH1-24) will be undertaken in healthy
volunteers, women taking an oestrogen-containing oral contraceptive pill (OCP), patients with
adrenal insufficiency and patients with low serum albumin. Serum cortisol in the samples
collected from healthy volunteers will be measured using GC-MS, Advia Centaur (Siemens),
Architect (Abbott), Modular Analytics E170 (Roche), Immulite 2000 (Siemens) and Access
(Beckman) automated immunoassays. The estimated lower reference limit for the 30 min cortisol
response to ACTH, defined as the 2.5th percentile of log-transformed concentrations, will be
determined in this healthy population and used as a cut-off in the patient groups studied.