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Spirometry Calculator

This PatientPlus article is written for healthcare professionals so the language may be more technical than the condition leaflets. You may find the abbreviations list helpful.

See also our record on Spirometry

Spirometry Calculator
Age Sex
Height (cm) Predicted
FEV1
FVC
FEV1/FVC Ratio
PEFR

This calculator uses an algorithm derived from healthy adult lifetime nonsmokers in Australia.1

Measurements made in Spirometry
AbbreviationMeasurementDescription
VC (SVC)Vital capacity (Slow vital capacity)Maximal amount of air exhaled steadily from full inspiration to maximal expiration (not time dependent). It should be >80% of predicted, reduced in restrictive disease.
FVCForced vital capacityVolume of lungs from full inspiration to forced maximal expiration. It is reduced in restrictive disease, and in obstructive disease if air trapping occurs.
FEV1Forced expiratory volume in one secondVolume of air expelled in the first second of a forced expiration. Reduced in both obstructive and restrictive disease.
FEV1% (FER)Forced expiratory ratio (FEV1/FVC)x100Percentage of FVC expelled in the first second of a forced expiration.
Normal in restrictive disease - reduced in obstructive disease.
FEF 25-75%Forced Expiratory Flow between 25-75%Average expiratory flow rate at the middle part of forced expiration. It is a more sensitive indication of what is happening in the middle/lower airways, but is not as reproducible as FEV1. Normal in restrictive disease.
PEFRPeak expiratory flow rateMaximum rate of airflow achieved during expiration

Document references

  1. Gore CJ, Crockett AJ, Pederson DG, et al; Spirometric standards for healthy adult lifetime nonsmokers in Australia. Eur Respir J. 1995 May;8(5):773-82. [abstract]

Acknowledgements

EMIS is grateful to Dr Huw Thomas for writing this article. The final copy has passed scrutiny by the independent Mentor GP reviewing team. ©EMIS 2010.
Document ID: 2797
Document Version: 23
Document Reference: bgp2357
Last Updated: 30 Jun 2009
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