Important Medical Disclaimer
This calculator is an educational and clinical decision support tool. Results DO NOT replace professional medical evaluation, laboratory tests, or clinical judgment. Always consult a qualified healthcare professional for diagnosis, treatment, and clinical decisions. Calculations are based on scientifically validated formulas but may not be applicable to all patients.
FEV1 Calculator (Forced Expiratory Volume)
Calculate predicted FEV1 using NHANES III formulas and classify severity of pulmonary obstruction.
Input Data
How It Works
FEV1 is the volume of air expired in the first second of a forced expiration. Predicted values are calculated based on age, height, and gender using NHANES III equations.
Clinical Use
Essential for diagnosis and staging of COPD, asthma, and other obstructive lung diseases.
Frequently Asked Questions
What is FEV1?
FEV1 (Forced Expiratory Volume in 1 second) is the amount of air that can be forcefully expired in one second.
When is FEV1 reduced?
FEV1 is reduced in obstructive diseases such as COPD, asthma, and bronchiolitis.
What does % of predicted mean?
It's the percentage of the observed value relative to the predicted value for the patient's age, height, and gender.
Is FEV1 < 50% severe?
Yes, FEV1 <50% of predicted indicates moderately severe or severe obstruction, requiring intensive treatment.