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Spirometry Training Program

Spirometry flow volume curve chart

Spirometry Reference Value Calculator

This calculator is used in determining normal spirometry reference values for use with NIOSH-Approved Spirometry Training Program courses.

To obtain the predicted and LLN values, at a minimum, you MUST:

  1. Choose the reference source Knudson or Hankinson
  2. Choose the gender and race of the subject
  3. Enter the age and height of the subject

To obtain the percent of predicted normal values – enter the worker’s reported values for FVC, FEV1, and FEF 25-75%.

Calculated Values
  FVC (L)* FEV1 (L)* FEV1/FVC% FEF25-75% (L/s)*
Percent Predicted
Lower Limit of Normal


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