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Expected peak expiratory flow
Predicted normal peak flow for adults by age, height and sex.
Expected peak expiratory flow
Sex
Age
years
Height
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When to use
- Providing a predicted-normal reference to interpret a patient's measured peak flow (e.g. in asthma).
Formula
Nunn & Gregg (EN13826 scale), height in cm, age in years. Men: PEF = exp(0.544 x ln(age) - 0.0151 x age - 74.7/height + 5.48). Women: PEF = exp(0.376 x ln(age) - 0.0121 x age - 58.8/height + 5.63).
Pearls and pitfalls
- Validated for ages 15-85; percent-predicted and personal best are more useful than a single reading.