This document discusses pulmonary function tests (PFTs), including the types of tests performed and what each tests evaluates. It describes common PFT measurements like forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), their ratios, and how obstructive, restrictive, and mixed patterns are interpreted from PFT results. Examples of PFTs in different pulmonary diseases are provided along with interpretations.

1. Pulmonary Function Test
Sarfraz Saleemi MD
Pulmonary Medicine
King Faisal Specialist Hospital & Research Center
Riyadh, Saudi Arabia

2. TYPES OF TESTS
 Spirometry
 Flow Volume Loop
 Bronchodilator response
 Lung volumes
 Diffusion capacity (DLCO)
 Bronchoprovocation testing – Methacholine, exercise etc;
 Maximum respiratory pressures – NIF, PEF, MVV, supine FVC
 6 MINUTE WALK TESTING
 cardiopulmonary exercise testing

3. PFT machines

4. PFT
• Volumes – measured value
• Capacities - sum of 2 or
more lung volumes
Inspiratory
Reserve
Volume
Normal values:
FVC > 80% predicted
FEV1> 80% predicted
FEV1/FVC > 70

5. • Forced vital capacity (FVC):
– Total volume of air that can be exhaled
forcefully after maximum inhalation
– Interpreted as % predicted
• Forced expiratory volume in 1
second: (FEV1)
– Volume of air forcefully expired from full
inflation (TLC) in the first second
– > 80 % Normal
– 70-79% Mild reduction
– 50%-69% Moderate reduction
– <49% Severe reduction
– <30% Very severe reduction

6. Flow volume loop

7. Obstructive Pattern
■ FEV1 <80%
■ FVC N or <80%
■ FEV1/FVC <70

8. Obstructive Lung Diseases
 Asthma
 COPD
- chronic bronchitis
- emphysema
 Bronchiectasis
 Cystic fibrosis
 Bronchiolitis
 Upper airway obstruction

9. Bronchodilator Response
 Degree to which FEV1 improves with inhaled
bronchodilator
 Documents reversible airflow obstruction
 Significant response if:
- FEV1 increases by 12% and >200ml

10. Restrictive Pattern
• FVC < 80%
 FEV1/FVC normal
 FEV1 N or < 80%

11. Restrictive Lung Diseases
 Chest wall - Kyphoscoliosis
 Neuromuscular – Myopathy,
Diaphragm paralysis
 Pleural disease
 Obesity
ILD
Lung Fibrosis
Parenchymal Extra-parenchymal

12. Flow-volume loop
Tracheal stenosis
Endotracheal tumors
Tracheomalacia
Polychondritis
Vocal cord paralysis
Laryngeal edema
Pharyngeal narrowing
-sleep apnea
-airway burn

13. Diffusion Capacity
 Diffusing capacity of lungs for CO
 Measures ability of lungs to transport inhaled gas
from alveoli to pulmonary capillaries
 Depends on:
- alveolar—capillary membrane
- hemoglobin concentration
- cardiac output

14. Diffusion Capacity (DLCO)

15. Diffusion Capacity
 Decreased DLCO
(<80% predicted)
 Obstructive lung disease
 Parenchymal disease
 Pulmonary vascular disease
 Anemia
 Increased DLCO
(>120-140% predicted)
 Asthma (or normal)
 Pulmonary hemorrhage
 Polycythemia
 Left to right shunt

16. FVC FEV1 FEV1/FVC TLC DLCO
Obstruction
Nor
Asthma N or
COPD
Restriction N or
ILD
Extra-
Parenchymal
Mixed
Interpretation
N

17. • Instant start of exhalation
• Rapid rise in flow to peak flow
• Sharp peak occurring
early in exhalation
• Smooth continuous fall in flow
without interruption
• Slow fall to RV
• Smooth continuous inhalation to
TLC
• Reproducible(5% OR 0.2L)
• Slow start
• Slow rise to peak flow
• Slow late peak
• Coarse flow with interruptions
• Abrupt end to RV
• Incomplete inhalation
• Non reproducible
Acceptable Not acceptable

18. FEV1/ FVC
LOW
OBSTRUCTION
LOW FEV1
REVERSIBLE
BA
IRREVERSIBLE
COPD
NORMAL
FVC LOW
TLC LOW
RESTRICTION
LOW DLCO NORMAL DLCO
PARENCHYMAL EXTRA PARENCHYMAL
Low DLCO normal DLCO
Emphysema
Ch, Broch

19. Test Ref. Measured % predicted
FVC (L) 4.07 3.80 93
FEV1 (L) 3.30 3.61 109
FEV1/FVC (%) 95
Normal

20. Test Ref. Measured % predicted
FVC (L) 4.44 3.41 77
FEV1 (L) 3.83 2.15 56
FEV1/FVC (%) 58
Obstruction

21. Test Ref. Measured % predicted
FVC (L) 3.36 1.84 54
FEV1 (L) 3.09 2.30 74
FEV1/FVC (%) 121
Restriction

22. Test Ref. Measured % predicted Post % change
FVC (L) 4.46 3.18 71.3 3.65
FEV1 (L) 3.84 1.85 48.1 2.19 18.7
FEV1/FVC (%) 58 62
Reversible
Obstruction

23. Test Ref. Measured % predicted Post % change
FVC (L) 4.11 3.57 79 3.84
FEV1 (L) 3.37 2.3 72 2.49 9
FEV1/FVC (%) 66 70.4
irreversible
Obstruction

24. Test Ref. Measured % predicted Post % change
FVC (L) 2.87 1.24 43 1.37
FEV1 (L) 2.16 0.49 23 0.57 17
FEV1/FVC (%) 39 42
Minimal reversible
Obstruction

25. Test Ref. Measured % predicted
FVC (L) 3.90 2.31 59
FEV1 (L) 2.90 2.29 74
FEV1/FVC (%) 99
TLC 4.70 3.19 67
DLCO 7.95 5.06 63
Restrictive lung disease

26. Test Ref. Measured % predicted
FVC (L) 4.26 3.02 69
FEV1 (L) 3.84 2.98 79
FEV1/FVC (%) 98
TLC 6.9 4.32 62
DLCO 9.65 8.26 87
Extra-parenchymal
restriction

27. Test Ref. Measured %
FVC (L) 4.44 4.01 87
FEV1 (L) 3.83 2.15 56
FEV1/FVC (%) 58
Upper airway
obstruction

28. Test Ref. Measured % predicted
FVC (L) 4.07 3.80 93
FEV1 (L) 3.30 3.61 109
FEV1/FVC (%) 95
TLC 6.7 6.2 92
DLCO 5.3 2.2 41
Pulmonary vascular
disease

29. Test Ref. Measured % predicted Post % change
FVC (L) 4.11 3.30 79
FEV1 (L) 3.37 2.03 60 2.15 9
FEV1/FVC (%) 61
TLC (L) 5.10 4.99 97.8
DLCO
(mmol/min/kpa)
8.94 2.46 30
Obstructive airway
Disease
COPD-emphysema

30. Test Ref. Measured % predicted
FVC (L) 3.21 2.17 67
FEV1 (L) 2.37 1.33 56
FEV1/FVC (%) 61
TLC (L) 5.10 3.59 70
DLCO (mmol/min/kpa) 4.94 2.46 49
Mixed Obstruction and
restriction

31. A 15 years old student presented with recurrent cough and
shortness of breath.
A pulmonary function test is done.
Measured
(L)
% age
predicted
Post-
broncho-
dilator (L)
%age
change
FVC 3.50 100 3.70
FEV1 2.30 75 2.70 17
FEV1/F
VC
65
What is the most likely diagnosis?
Significant Reversibility
>12% and >200ml
Bronchial Asthma

32. A 57 yrs old man with 30 pack yrs of smoking presented with
progressive dyspnea for one year.
PFT is shown:
measured % age
predicted
post %age
change
FVC 3.05 88 3.11
FEV1 1.36 45 1.47 9
FEV1/FVC 52
TLC 4.99 97
DLCO 2.46 27
What is the most likely cause of this patient’s dyspnea?
COPD

33. What is the most likely Diagnosis?
A. Bronchial Asthma
B. COPD
C. Interstitial Lung Disease
D. Obesity Hypoventilation Syndrome
measured % age predicted
FVC 1.40 39
FEV1 1.75 55
FEV1/FVC 96
TLC 3.11 58
DLCO 7.44 87
• A 45 yrs old female with a BMI of 32 presented with
chronic hypercapnic respiratory failure.
• PFT is shown.

34. • A 20 yrs old female presents with progressive dyspnea for one
year. PFT result is shown:
measured % age predicted
FVC 2.02 80
FEV1 1.91 91
FEV1/FVC 94
TLC 6.99 85
DLCO 2.71 37
What is the most likely diagnosis?
A. Bronchiolitis Obliterans
B. Restrictive lung disease
C. Pulmonary hypertension
D. Alveolar hemorrhage

35. A 24-year-old man presents with shortness of breath for 6 months.
A flow-volume loop is shown
How is the most likely diagnosis?
A. Bronchial asthma
B. COPD
C. ILD
D. Fixed upper airway obstruction

36. A 20-years-old woman who is known to have SLE presents
with acute shortness of breath and mild hemoptysis.
Pulmonary function test is shown.
Test Result
% predicted
Normal value
FVC 65 >80
FEV1 79 >80
FEV1/FVC ratio 90 70
DLCO 160 >80
What is the most likely Diagnosis?
A. Severe Anemia
B. Cryptogenic organizing pneumonia
C. Bronchiolitis Obliterans
D. Pulmonary alveolar hemorrhage

37. Which of the following is used to follow disease severity in
COPD patients?
a. Total lung capacity (TLC)
b. Degree of responsiveness to bronchodilators
c. Forced vital capacity (FVC)
d. Forced expiratory volume in 1 second
e. Diffusing capacity (DLCO)

38. Thanks