Peak Expiratory Flow (PEF)
- Sample Type
- Standard
- Fasting
- No
- Unit
- L/min
PEF measures the maximum speed of expiration. It is a vital component of a Pulmonary Function Test for monitoring large airway patency. It is primarily used in the management of asthma to detect early signs of exacerbation and to assess the effectiveness of bronchodilator therapy.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
PEF is highly 'effort-dependent.' Results can vary significantly based on patient technique, posture, and time of day (diurnal variation). It may not accurately reflect small-airway disease which is better assessed via spirometry (FEV1/FVC).
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Peak Expiratory Flow (PEF):
Official Sources
Research & Guidelines
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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