Expected Peak Expiratory Flow (PEF) Calculator
Estimates predicted peak expiratory flow (PEF) based on sex, age, and height using Nunn-Gregg or ECCS reference equations. Used to assess asthma severity (% predicted PEF).
Score interpretation
PEF below 33 % of best or predicted (SIGN 158).
→ Emergency treatment; senior and critical-care input.
PEF 33–50 % of best or predicted (SIGN 158).
→ Treat as acute severe asthma per BTS/SIGN guidance.
PEF over 50 % and up to 75 % of best or predicted.
→ Treat the exacerbation; reassess response.
PEF above 75 % of best or predicted.
→ Not in the acute-exacerbation PEF range; interpret with symptoms.
Interpretation bands for the Peak Flow (PEF). Apply clinical judgement and local guidance.
References
Related
Curated clinical cross-links plus same-class fallbacks.
- Nitric Oxide (Inhaled — iNO) · Selective Pulmonary Vasodilator
- Selexipag · Pulmonary Arterial Hypertension
- Macitentan · Pulmonary Arterial Hypertension
- Tezepelumab (CRSwNP / Severe Asthma) · Anti-TSLP (Thymic Stromal Lymphopoietin) Monoclonal Antibody
- Salbutamol (Paediatric — Asthma/Wheeze) · Short-Acting Beta-2 Agonist (SABA)
- Prednisolone (Paediatric) · Corticosteroid — Asthma Exacerbation / Croup / Nephrotic Syndrome / IBD
- Acute Asthma in Adults · BTS/SIGN British Guideline on Asthma 2019; NICE NG80
- Pulmonary Embolism Assessment · NICE NG158; ESC 2019 PE Guidelines
- Acute Exacerbation of COPD (AECOPD) · NICE NG115; GOLD 2024
- Spontaneous Pneumothorax (Adult) · BTS Pleural Disease 2023
- Atypical Pneumonia (Legionella / Mycoplasma / Chlamydophila) · BTS 2023; IDSA
- COPD Exacerbation Management · NICE NG115 / GOLD 2024
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.