Screening and testing

Screening and testing

When assessing severe asthma, it is important to evaluate the patient’s inflammatory phenotype – whether they have type 2 inflammation or not.1

According to the GINA Guidelines, when type 2 inflammation is suspected the following should be checked:1

  • Blood eosinophils ≥150μl and/or
  • Fractional exhaled nitric oxide (FeNO) ≥20 ppb and/or


Repeat blood eosinophils and FeNO up to 3x on lowest possible oral corticosteroid dose:

  • Sputum eosinophils ≥2% and/or
  • Presence of allergens driving symptoms and/or
  • Need for maintenance oral corticosteroid

It is important to note that just because IgE, eosinophils or FeNO levels are high in an individual patient with severe asthma, it does not necessarily mean that these cells and molecules are the principle drivers of disease activity.1


  1. 1.Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention, 2020. Available from: (accessed November 2020).