A new at-home saliva test that could offer a simpler and more rapid way to diagnose adrenal insufficiency among patients at high risk has been unveiled by researchers at the University of Sheffield. The test works by detecting waking cortisol at its peak first thing in the morning in saliva rather than blood.
This holds the potential to avoid the need for the traditional lengthy hospital screening procedure of the adrenocorticotropin (ACTH) stimulation test, also called the short Synacthen test, that requires clinic attendance and venesection with two blood samples at 30 minute intervals. The possibility of an at-home test was welcomed by patient groups.
The new saliva test was put to the test in a 3-year prospective, diagnostic accuracy study of 220 patients attending Sheffield Teaching Hospitals' endocrine unit, either as an outpatient or as a patient being treated by another specialty department. All the patients had been identified as being at risk of adrenal insufficiency and given an at-home kit to check saliva samples at their home on waking in the morning. They then attended the clinical facility for an ACTH stimulation test. Salivary cortisone was measured by liquid chromatography–tandem mass spectrometry.
Most Patients Preferred the Home Saliva Test
Results, published inthe New England Journal of Medicine - Evidence, showed that the prevalence of adrenal insufficiency as measured by the ACTH stimulation test was 44%. "Waking salivary cortisone data provided information similar to that of an ACTH stimulation test in 70% of participants," the authors said. Furthermore, 83% of patients preferred home salivary collection to clinic attendance.
Patients reported that they found the saliva tests less painful, and taking tests at home helped to reduce their anxiety, with this having the added benefit of improving their overall health. Avoiding the need for repeated round trips to hospital also reduced the time they had to take off work. The rapid diagnosis also meant that patients were able to be treated imminently and avert an adrenal crisis on occasion – something to which 6% to 8% of individuals with adrenal insufficiency are vulnerable each year, for which diagnosis is often delayed and that carries a 6% mortality rate.
The researchers concluded that the at-home test using saliva rather than blood "provides a faster and more convenient way to diagnose adrenal insufficiency". The study data also showed that the new test was able to make an accurate diagnosis in 70% of patients at risk of adrenal insufficiency, "saving time and money for both the patient and the NHS", the team, said.
Test Could Deliver Savings for NHS
The researchers estimated that if the at-home test were delivered across the wider NHS, the number of standard hospital-based diagnostic investigations could be reduced by more than a third, from 92,000 annual patient visits a year to just 23,000.
First author Dr Miguel Debono, consultant endocrinologist at Sheffield Teaching Hospitals NHS Foundation Trust and honorary senior lecturer at the University of Sheffield’s Department of Oncology and Metabolism, who developed the test in partnership with Richard Ross, professor of endocrinology at the University of Sheffield, said:"Up to 3% of the population take oral steroids to control anti-inflammatory conditions such as asthma, arthritis and inflammatory bowel disease, and half of these patients suffer with adrenal insufficiency.
"We are delighted to be presenting the findings of this important study as this shows that testing for waking cortisol through a simple at-home test provides a more rapid and convenient way to screen for the condition, which is just as accurate as a blood test, and enables patients to get an early diagnosis, which can be key in preventing an adrenal crisis."
The study was funded through a National Institute for Health and Care Research (NIHR) grant. Professor Marian Knight, programme director for the National Institute for Health and Care Research (NIHR)'s Research for Patient Benefit Programme, said: "This is a great example of NIHR-funded research that will bring immediate benefits to patients - giving them the option to do a simple saliva test at home instead of going to hospital for a blood test, to help spot people at risk of adrenal insufficiency."
Asked to comment by Medscape News UK, Vick Smith, executive director of the Addison's Disease Self Help Group (ADSHG), said: "The ADSHG welcomes the encouraging findings of this study. Untreated Addison's disease can be fatal, so we need quick, reliable, accessible and economical routes to diagnosis. If, as this study suggests, we could potentially see the development of a test that can be taken at home, the hope would be that testing for adrenal insufficiency would become as routine as checking for other endocrine conditions such as underactive thyroid or diabetes.
"We are grateful to Dr Miguel Debono, Professor Richard Ross, Professor Marian Knight and all who have contributed to this important study. We work closely with the medical profession to fund new research, raise awareness of the condition and improve the quality of care for people with adrenal insufficiency. The ADSHG offers a range of resources for healthcare professionals, people with Addison's and the people who care for them."
The research team is now seeking further funding to make the test available to the wider NHS.