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Covid-19 Primary Care Resources

Diagnosing asthma

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Structured clinical assessments, validated questionnaires and tools to support peak flow self measurements at home

This information in sourced from the Primary Care Respiratory SocietySIGNNICE, NHS England and the Centre for Evidence-Based Medicine (CEBM):


  • Spirometry is frequently normal in patients with asthma (unless they are experiencing a current worsening of their asthma symptoms)
  • Most pulmonary function tests have the potential to spread Covid‑19 including spirometry, FeNO and PEFR
  • Only carry out pulmonary function tests for urgent cases and if the results will have a direct impact on patient care
  • Spirometry and FeNO should be reserved for those patients with an intermediate probability of asthma (ideally through a primary care-based respiratory diagnostic service)
  • If PEFR evaluation in clinic is considered necessary this can be carried out using the patients own PEF meter and disposable mouthpiece in a room with an open window or outside the building
  • Guidance from the Association for Respiratory Technology and Physiology (ARTP) and the Primary Care Respiratory Society (PCRS) on 3 June – developed by an NHS England ‘task and finish group’ – said that GP practices should begin to restore spirometry ‘as a matter of urgency’ and a ‘priority’.

Structured clinical assessment

  • Diagnosis of patients with suspected asthma can, in many cases, be made without the need for testing procedures
  • structured clinical assessment should include a detailed history, examination and review of the patient’s clinical records including the results of any previous PEFR, spirometry or blood eosinophils
  • Patients with a high probability of asthma following a structured clinical assessment can be managed with a trial of treatment with peak flow monitoring at home
  • It is important to ensure that the patient is well trained to undertake peak flow readings at home using maximal respiratory effort and in accurately recording the measurements
  • This training can take place via video consultation
  • Where peak flow monitoring is not possible use of a validated symptom questionnaire is recommended eg the Asthma Control Test (paper based version or weblink are freely available)

Criteria for a high probability of asthma include:

  • Recurrent episodes of symptoms
  • Wheeze confirmed by a health care professional
  • A personal or family history of asthma
  • A past record of variable airflow obstruction
  • No features to suggest an alternate diagnosis
  • Clear and repeated evidence of 20% variability of PEFR collected using a PEFR diary

See also:

Asthma – managing exacerbations