Welch Allyn CP 200 Spirometry Option - User Manual - Manual (Page 73)

Directions for Use Appendix D Predictive Norms, etc. 69
About Norm Extrapolation
Extrapolation is the practice of applying a norm’s formula to a patient who doesn’t fit that
norm’s demographics. For example, if you were testing an 88-year-old man, and the
primary (selected) norm were based on males 85 or younger, the predicted values would
be extrapolated values.
• When it takes place, extrapolation is indicated in the test record.
• Pediatric norms do not provide any age, weight, or height extrapolation.
• Adult norms allow extrapolation of age up, but not down.
• Adult norms allow extrapolation of height, weight, and smoke years, up and down.
About Race Adjustment
Although expected values for certain parameters vary significantly between ethnic
groups, some norm studies do not include separate regression equations for different
races. For those studies, the following table describes the adjustments made by the
CP 200 software for the FVC and FEV1 predicted values. Where applicable, norm values
are multiplied by the percentages identified in the following table.
Race Choices FVC & FEV1 Recommendation Source
Caucasian No adjustment —
Black 88% ATS
Asian 94% NIOSH
Hispanic No adjustment None found
Native American 94% NIOSH
Polynesian 94% NIOSH
Aboriginal 94% NIOSH
Indian 94% NIOSH
Note Race adjustment applies for adults only.
If a race adjustment percentage is used, the same adjustment is applied to the
LLN value.