ATS Criteria for Acceptable Spirometry


Acceptable flow-volume loop includes:
  • Satisfactory start-of-test
  • Minimum 6-second exhalation
  • End-of-test criteria
  • < 30 mL change for at least 1 s after 6-second exhalation
  • Subject unable to continue or is unsafe to continue
  • Obvious plateau

Acceptable flow-volume loop must not have:
  • Unsatisfactory start of exhalation (Extrapolated volume < 5% of FVC or 150 mL)
  • Cough during first second
  • Early termination of exhalation
  • Valsalva maneuver or hesitation that causes cessation of airflow
  • Leak
  • Obstructed mouthpiece

Reproducibility:
  • FVC: Next largest and largest must be within 200 mL
  • FEV1: Next largest and largest must be within 200 mL

Bronchodilator change:
  • 200 mL AND 12% improvement FEV1 and/or FVC
    • Note that the upper limit of normal for short acting bronchodilator change in a population of healthy children and adults is 6-9%

ats_criteria_for_spirometry.png

Obstruction Definitions

A fixed percentage below the predicted FEV1/FVC
  • For example, 5% or more below the predicted FEV1/FVC; if the predicted FEV1/FVC is 72%, a value of 67% would be considered abnormal
Below relatively arbitrary aged-based norms (NAEPP EPR3)
“normal” FEV1/FVC for a person
  • 8-19 yo: 85%
  • 20-39 yo: 80%
  • 40-59 yo: 75%
  • 60-80 yo: 70%
Global Initiative for Chronic Obstructive Lung Disease consortium
  • An FEV1/FVC <70% after administration of a short-acting bronchodilator (e.g., 4 puffs of albuterol through a spacer)
ATS/European Respiratory Society Task Force on the Standardisation of Lung Function Testing
  • An FEV1/FVC (or FEV1-to-VC ratio) less than the lower limits of normal defined as less than the fifth percentile predicted


Bronchodilator Reversibility Definitions

  • Note that the upper limit of normal for short acting bronchodilator change in a population of healthy children and adults is 6-9%

Bronchodilator_reversibility_definitions.png


FEV1 Severity

Degree of Severity-------
FEV1 %predicted-------
Mild
>70
Moderate
60-69
Moderate-severe
50-59
Severe
35-49
Very severe
<35


COPD Staging (GOLD)

Stage
FEV1/FVC-------
FEV1 %predicted
I - Mild
<0.70
80
II - Moderate
<0.70
50-80
III - Severe
<0.70
30-50
IV - Very severe-------
<0.70
<30 or <50 plus chronic respiratory failure-------


CDC Spirometry Reference Value Calculator


Classic Flow Volume Curves

Classic flow volume curves.png


References