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Pulmonary Function Test Lower Limit of Normal
Aka: Pulmonary Function Test Lower Limit of Normal, Spirometry Lower Limit of Normal, PFT LLN
- See Also
- Pulmonary Function Test
- Lung Volumes
- Diffusing Capacity
- Inhalation Challenge Test
- Exercise Spirometry
- Functional Residual Capacity
- Vital Capacity
- Peak Expiratory Flow Rate (PEFR)
- Obstructive Lung Disease
- Restrictive Lung Disease
- Indications
- Pulmonary Function Test Interpretation (Used in ATS Guidelines)
- Background
- Based on Third National Health and Nutrition Examination Survey (NHANES III) PFT data
- Calculated the lowest 5% (fifth percentile) cut-offs for FEV1 to FVC, FVC and FEV1
- Replaces GOLD Criteria which are less accurate
- Miss up to 50% of young adults with Obstructive Lung Disease and
- Overdiagnose Obstructive Lung Disease in healthy non-smokers
- Recently manufactured PFT software calculates the LLN based on patient age, gender and height
- Resources
- Spirometry Calculator (CDC NIOSH)
- https://www.cdc.gov/niosh/topics/spirometry/refcalculator.html
- Online calculator
- http://hankconsulting.com/RefCal.html
- References
- Johnson (2014) Am Fam Physician 89(5): 359-66 [PubMed]
- Mannino (2007) Thorax 62(3): 237-41 [PubMed]