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

NCT ID: NCT00851942

Last Updated: 2020-08-12

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE4
• Total Enrollment: 165 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2008-09-30
• Study Completion Date: 2013-01-31

Brief 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.

Detailed Description

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 Synacthen® test cut-offs therefore rely on historical reference ranges which have become outdated. A re-evaluation of the cortisol cut-off is required to ensure that patients are not incorrectly classified.

It has been long been recognised that oestrogens (including ethinyloestradiol prescribed in combined oral contraceptive pills) increase total (but not free) serum cortisol levels. The degree of increase is related to the dose used and is thought to be due to an elevation in cortisol binding globulin (CBG). However, no comparisons of total serum cortisol in response to Synacthen® have been performed between women taking oestrogens and those who are not. Knowledge of the salivary cortisol response may also be useful in patients with decreased serum CBG concentrations e.g. severe nephrotic syndrome in whom the serum cortisol response may be misleading. The investigators therefore plan to measure salivary cortisol as part of the investigators' study protocol to assess the response of free cortisol.

17 Hydroxyprogesterone (17OHP) is an intermediate in the biosynthesis of cortisol. Deficiency of 21-hydroxylase enzyme activity leads to an increased concentration of 17OHP in the peripheral circulation. The short Synacthen® test can be used to assist in diagnosis of mild cases of congenital adrenal hyperplasia. Current reference ranges are taken from the literature.

Conditions

Healthy; Adrenal Insufficiency; Hypopituitarism

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: DIAGNOSTIC
• Blinding Strategy: NONE

Study Groups

Synacthen 250 micrograms

IV injection of 250 micrograms of Synacthen in 1m

Group Type: EXPERIMENTAL

Synacthen (Tetracosactrin)

Intervention Type: DRUG

IV injection of 250 micrograms of Synacthen in 1ml

Interventions

Synacthen (Tetracosactrin)

IV injection of 250 micrograms of Synacthen in 1ml

Intervention Type: DRUG

Other Intervention Names

Synacthen

Eligibility Criteria

Inclusion Criteria

• Volunteers will be in self-proclaimed good health
• Volunteers will be free of illness on the day of testing
• Volunteers will not be taking drug therapy.
• Patients will be free of intercurrent illness on the day of testing
• Patients will have a confirmed diagnosis of hypoadrenalism or hypopituitarism

Exclusion Criteria

• Is pregnant or lactating. Females of childbearing potential must have a negative pregnancy test before enrollment onto the study. Non-child bearing potential is defined as post-menopausal for at least 1 year, surgical sterilisation or hysterectomy at least three months before the start of the study,
• Is using corticosteroids,
• has any significant intercurrent disease,
• has a history of thyroid or other autoimmune disease,
• has a previous history of hypersensitivity to Synacthen®,
• has a previous history of asthma
• has a history of allergic disorder
• has any mental condition rendering the patient unable to understand the nature or possible consequences of the study, and/or evidence of an uncooperative attitude.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 80 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Cardiff University

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Aled Rees, MB BCh, PhD

Role: PRINCIPAL_INVESTIGATOR

Cardiff University

Locations

Clinical Research Facility, University Hospital of Wales

Cardiff, South Glamorgan, United Kingdom

Countries

United Kingdom

References

Owen LJ, Adaway JE, Davies S, Neale S, El-Farhan N, Ducroq D, Evans C, Rees DA, MacKenzie F, Keevil BG. Development of a rapid assay for the analysis of serum cortisol and its implementation into a routine service laboratory. Ann Clin Biochem. 2013 Jul;50(Pt 4):345-52. doi: 10.1177/0004563212473448. Epub 2013 Jun 12.

Reference Type: DERIVED

PMID: 23761380 (View on PubMed)

Other Identifiers

SPON 431-07

Identifier Type: -

Identifier Source: org_study_id