Step 2 – Perform a test to support the patient’s diagnosis
Start by undertaking a structured clinical assessment to assess the probability of asthma. This should be based on:
- a history of recurrent episodes (attacks) of symptoms, ideally corroborated by variable peak flows when symptomatic and asymptomatic
- symptoms of wheeze, cough, breathlessness and chest tightness that vary over time
- recorded observation of wheeze heard by a healthcare professional
- personal/family history of other atopic conditions (in particular, atopic eczema/ dermatitis, allergic rhinitis)
- no symptoms/signs to suggest alternative diagnoses
The next step is to ask the patient to complete a two week Peak Flow Diary, taking one measurement in the morning and one measurement in the evening, and recording the results. This record can be a paper diary, or you can advise your patient to download the Asthmahub or Asthmahub for parents app, with an in-built peak flow diary.
Once the patient returns the PEF diary, record these results in the patient’s notes with the correct code for a peak flow diary:
- Read Code: 66YY
- Or SNOMED code: 401011001
Check the Peak Flow Diary for evidence of “dips”; if there are “dips” in the peak flow measurement of more than 20%, the diagnosis of Asthma has been confirmed. Make sure the diagnostic code reflects this:
- Read Code: H33
- SNOMED Code: 195967001
For those patients who did not experience significant “dips” in their Peak Flow measurement, try an alternative diagnostic test:
- Spirometry
- Spirometry with reversibility
- Peak flow with reversibility
- Fractional exhaled nitric oxide
Of course, some patients will be stable on their medication and will not show evidence of objective variability for this reason. Click through the scenarios below for more details.