Pneumology calculator
Spirometry Interpretation | ERS/ATS 2022
LLN and z-score spirometry interpretation based on ERS/ATS style reporting.
Output style
The conclusion is written in clinical English, for example: “Severe obstructive ventilatory impairment (FEV1 48% predicted; FEV1 z-score −3.20).”
1
Pre-bronchodilator values
Complete FEV1, FVC and FEV1/FVC. LLN or z-score is preferred for ERS/ATS-style interpretation.
Parameter
Measured
Predicted
LLN
ULN
z-score
2
Lung volumes, optional
Restriction and mixed ventilatory impairment are confirmed by low TLC. Complete only if lung volumes are available.
Parameter
Measured
Predicted
LLN
ULN
z-score
3
Post-bronchodilator values, optional
Positive bronchodilator response: increase >10% of the predicted value for FEV1 or FVC.
The result will appear here
Enter the values, then press “Interpret”.
Method notes
- Obstruction: FEV1/FVC below LLN or z-score < −1.645.
- Restriction: TLC below LLN or z-score < −1.645. Low FVC with preserved FEV1/FVC suggests restriction but does not confirm it without TLC.
- Mixed ventilatory impairment: low FEV1/FVC plus low TLC.
- ERS/ATS severity is displayed with z-score categories: mild, moderate, severe.
- Classic FEV1 % predicted wording is also available for teaching/reporting style: mild, moderate, severe, very severe.
- FEF25–75 is presented as supplementary information, not as an isolated diagnostic criterion.