8th December 2016
There is no definitive diagnostic test for asthma. As it becomes clearer that there are several different types of asthma we will also need simple and reliable tests to identify what type of asthma someone has so that specific treatment can be given.
For most people with asthma, a diagnosis is made following a series of tests and trials of different treatments to see if they work. For others, diagnosis will involve travelling to specialist clinics and undergoing a number of invasive and expensive tests, and trying medications over many months that may ultimately be found to be inappropriate or ineffective. In the 21st century we can and should do better than this.
How could we diagnose asthma more accurately?
After years of slow but steady research, researchers are on the cusp of developing more accurate diagnostic tests for asthma. Importantly, the need for new tests was ranked top priority in the list of asthma research priorities identified through the recent Asthma UK-led European Asthma Research and Innovation Partnership by people with asthma, researchers, health professionals and the pharmaceutical industry.
As part of this work, a specific report on diagnosis of asthma examined the evidence for existing and emerging diagnostic tools. The most commonly known diagnostic tests include the use of peak flow measurement and spirometry, which alone are not particularly accurate. Other tests that are often used by specialists include the analysis of sputum – coughed up mucus from the respiratory tract – but it is not an easy test to do and it is not often feasible to use it in young children.
The report also highlighted the recent exciting developments in our scientific understanding of different markers of asthma at a molecular or gene-level, known as biomarkers, which have the potential to identify different types of asthma. It’s thought that these biomarkers could complement existing tests such as lung function tests to generate clear profiles of different types of asthma as they emerge.
For example, a type of asthma called eosinophilic asthma – named after the white blood cells that cause it – can now be identified through measuring eosinophils in the blood. This means that people likely to respond to the new recently-approved drug for severe asthma, mepolizumab, can be identified via a simple blood test (alongside other tests as necessary). There has also been research into biomarkers found in the urine which shows promise in identifying people likely to be at immediate risk of asthma asthma attack which would easy to perform and amazingly helpful. And in September this year, researchers found that a saliva test could be used to diagnose asthma, though the specific biomarkers need to be validated in further, longer term studies studies.
This goes to the heart of the problem. While we know that some of these tests are promising, we desperately need more research targeted at developing accurate, non-invasive, inexpensive tests to diagnose asthma and its sub-types so that we get people started on the right treatment early and avoid giving treatment to those that don’t need it or wouldn't benefit. Difficult, painful, time-consuming or expensive tests are unlikely to be widely accepted or used by people with asthma or the NHS.
What is Asthma UK doing to move this forwards?
This week, we are attending the British Thoracic Society’s Winter Conference in London, bringing together a small number of leading asthma researchers, medical specialists and people with asthma to discuss the best way to get this important research funded and performed. Together, we want to identify the best scientists, techniques and devices to create opportunities for expanding and focussing research in this area in the UK with a view to massively speeding up the development of new diagnostic tests.
Being able to accurately diagnose asthma would be absolutely transformative. Not only would nurses and doctors be able to prescribe the drugs that would be most effective for people with specific types of asthma, they may also be able to identify people at risk of a life threatening asthma attack. This is the challenge we need to address to transform the lives of people with asthma.