PFT Interpretation Steps

Question 1

Step 1

Answer 1

Greater than 70% Normal or Restrictive

Less than 70% Obstructive

Question 2

Step 2

Answer 2

Severity of Obstruction
FEV1 over 70% = Mild
FEV1 60 - 70% = Moderate
FEV1 50 - 60% = Moderately Severe 
FEV1 35 - 50% = Severe
FEV1 less that 35% = Very Severe

Question 3

Step 3

Answer 3

Post - Pre/Pre X 100%

Greater than 12% Improvement is Reversible airway disease

Question 4

Step 4

Answer 4

Normal Range: 80 - 120% of predicted
TLC Greater than 120% = hyperinflation/Obstructive
TLC less than 80% =Restrictive 
70-80% = Mild
60-70% = Moderate
50-60% = Moderately Severe 
Less than 50% = Severe

Question 5

Step 5

Answer 5

Normal Range is less than 35%

Greater than 35% = Air trapping

Question 6

Step 6

Answer 6

Normal Range: 80-120%
Obstructive Disease:
-Decreased in Emphysema
-Normal in Chronic bronchitis
-Normal or increased in Asthma
Restrictive Disease:
-Decreased in parenchymal disease
-Normal in non-parenchymal disease

Question 7

Step 7

Answer 7

If values in 1-6 are normal look at FEF 25-75

Less than 80% pt has early obstruction