Simple saliva test used to diagnose adrenal insufficiency

The use of an at-home test that uses saliva rather than blood to diagnose adrenal insufficiency, developed by scientists at the University of Sheffield, could reduce the number of hospital tests currently required by up to 70%.

Adrenal insufficiency is a common disorder of the adrenal glands that occurs when the body is no longer able to make cortisol — a major hormone that helps the body overcome stress and infections as well as regulating body sugars, proteins and fats. It is particularly common in those who take oral steroids for other medical conditions, as the body’s natural cortisol-making response shuts down while this function is temporarily taken over by the synthetic steroid. Up to 3% of the population take oral steroids to help with a broad range of inflammatory conditions, with around 50% of these suffering with adrenal insufficiency.

“Cortisol is a vital stress hormone from the adrenal gland and cortisol deficiency, adrenal insufficiency, also called Addison’s disease, can result in an adrenal crisis which if untreated can be life-threatening,” said Richard Ross, Professor of Endocrinology at the University of Sheffield. “A common cause is anti-inflammatory steroid treatment which is widely prescribed for conditions such as asthma, arthritis and inflammatory bowel disease. These people are at risk of adrenal insufficiency. The diagnosis is often made late as currently patients have to go to hospital for blood tests.”

Over 200 patients attending Sheffield Teaching Hospitals NHS Foundation Trust’s Endocrine Unit, identified as being at risk of adrenal insufficiency due to long-term steroid use to treat other conditions, were given swabs and a video showing them how to produce a saliva sample. The samples were taken in the morning at home.

The majority of patients reported they preferred this method to having to go to the hospital for a short Synacthen test (SST). This is an invasive screening procedure which requires patients to attend a one-hour appointment and to have their blood taken and measured both before and after an injection of tetracosactrin, a diagnostic agent.

The findings of the study, published in NEJM Evidence, show that when this new method of screening was implemented, 70% of patient visits for diagnostic tests were prevented. The researchers estimate that this could reduce the number of SSTs undertaken for adrenal insufficiency diagnostic investigations across the whole of England from 92,000 visits per year to just 23,000. Ultimately, the test is cheaper and should mean that diagnosis is more efficient.

“Presently the tests used to make this diagnosis are complex and necessitate visits to hospital with long waiting times, and testing is expensive,” said Dr Miguel Debono, Consultant Endocrinologist at Sheffield Teaching Hospitals NHS Foundation Trust. “Rollout of waking salivary cortisone to clinical care will allow a more rapid diagnosis of adrenal insufficiency by a convenient, simple test which has been shown to be accurate and cheaper and can be carried out at home.”

“The new test checks for deficiency when people wake in the morning when there is a cortisol peak,” Ross added. “Rather than tests that involve blood samples and an injection, the saliva test is proven to be as good as a blood test, and is more efficient.”

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