The updated guidance marks the first time NICE has set out the ‘most effective’ way to diagnose asthma.
The current lack of a gold standard on asthma diagnosis may have led to many patients going undiagnosed and almost a third (30%) of patients on asthma medication receiving treatment they do not need, NICE said.
The latest draft guidance lays out which tests to use and in what order they should be used to diagnose patients. The resultant ‘diagnostic algorithms’ are presented in flow charts within the guidance.
GP Dr John Haughney, past chairman of the Primary Care Respiratory Society (PCRS UK) welcomed the guidance. ‘I’m delighted that NICE support the need to get objective evidence of asthma,' he said.
'We might be committing people to life-long therapy, so we want to be sure we’ve got the diagnosis right.’
But he warned that many GPs do not have routine access to all of the tests the new guidance recommends.
Use spirometry test first
The guidance recommends that GPs use spirometry as the first-line investigation for asthma in adults and children over five.
Recommending the test for children marks a ‘significant change in practice’, and GPs will need to ‘develop the knowledge to use it effectively with children’, the guidance warns.
Should the patient test positive for obstructive spirometry, the guidance then recommends a bronchodilator reversibility (BDR) test followed by a FeNO test, depending on the patient’s age and results. Commissioners will be expected to ensure GPs have adequate access to the latter and training in how to use it.
If the GP remains uncertain of the patient’s diagnosis following the earlier tests, they should consider offering a bronchial challenge test.
As availability of this test is rare in primary care, GPs will have to ensure they are aware of the test’s benefits ‘to ensure appropriate referral and effective diagnosis’.
Accurate diagnosis 'a problem'
Professor Mark Baker, director of clinical practice at NICE said: ‘Accurate diagnosis of asthma has been a significant problem which means that people may be wrongly diagnosed or cases might be missed in others. Our aim with this guideline is to give clarity and set out the most clinical and cost effective ways to diagnose and monitor asthma based on the best available evidence.
‘We now want to hear from all those who provide care for people with asthma in the NHS to ensure all relevant views are considered for the final guideline.’
The guidance also recommends that GPs use a validated questionnaire to monitor asthma control in patients every time they have a review.
There are currently 4.1m people in the UK receiving treatment for asthma. The condition is estimated to affect 235m worldwide.