Choosing Spirometry Prediction Equations for Indian Patients
Spirometry results are compared with "predicted" values for a healthy person of the same age, sex and height. Which equation you use can change whether a result looks normal or abnormal.
Why equations matter
Lung function varies between populations. Equations derived from other populations may over- or under-estimate normal values for Indian patients, which leads to misclassification.
Options in practice
- Indian-derived equations. Several regional studies have produced equations for Indian adults and children.
- Global multi-ethnic equations (GLI). The Global Lung Function Initiative published multi-ethnic equations in 2012 and later race-neutral equations. Many labs worldwide use GLI.
- Older ATS/ECCS tables. Still found in many devices.
The SPIROEXCELL software includes Indian, ATS and ECCS prediction tables.
Practical recommendations
- Choose one approach for your lab after reviewing current guidance and your patient population.
- Configure every device the same way.
- Print the equation used on reports.
- Avoid mid-stream changes. If you must switch, note it clearly.
- Use LLN or z-scores where possible rather than fixed percentages alone.
Accurate inputs
Measure height accurately with a stadiometer, record age precisely and enter sex correctly. Small errors shift predicted values.
See spirometry interpretation basics and the PFT machine price guide.
PFT Machine (PC-Based Spirometer)
USB PC-based spirometer with digital turbine and automatic interpretation. ₹35,000 – ₹50,000
Frequently Asked Questions
Does SPIROEXCELL include Indian equations?
Yes, it includes Indian, ATS and ECCS prediction tables.
What is GLI?
The Global Lung Function Initiative provides multi-ethnic reference equations, with newer race-neutral versions.
Should I change equations mid-way?
Avoid switching without noting it, as trends may appear to change.
This article is for general information for healthcare buyers and professionals and is not medical advice. Clinical decisions should be made by qualified practitioners.
