Welcome To The Pulmonary Function Room


Pulmonary Function Tests - A Systematic Way To Interpretation

There is a systematic way to read the PFT and be able to evaluate it for the presence of obstructive or restrictive disease. The following steps will be helpful.

  1. Step 1. Look at the forced vital capacity (FVC) to see if it is within normal limits.
  2. Step 2. Look at the forced expiratory volume in one second (FEV1) and determine if it is within normal limits.
  3. Step 3. If both FVC and FEV1 are normal, then you do not have to go any further - the patient has a normal PFT test.
  4. Step 4. If FVC and/or FEV1 are low, then the presence of disease is highly likely.
  5. Step 5. If Step 4 indicates that there is disease then you need to go to the %predicted for FEV1/FVC. If the %predicted for FEV1/FVC is 88%-90% or higher, then the patient has a restricted lung disease. If the %predicted for FEV1/FVC is 69% or lower, then the patient has an obstructed lung disease.

How Do You Tell If The Patient Is Normal or Has Mild, Moderate or Severe Pulmonary Disease ?

There are a number of systems which physicians use to determine the severity of disease. Here is just one way that is very commonly used :

In most good spirometers on the market today, there is a set of normal tables (sometimes multiple sets of tables) which can be chosen as you perform the PFT. Also, there are interpretive microchips in the PFT machines which will tell you what the diagnosis is for a particular patient. These two features make it easy for the clinician to immediately see what the predicted values (normal table values) are for a specific patient and whether or not the PFT has a normal observed outcome. The PFT data are examined by the computerized spirometer and a diagnosis of obstructive or restrictive disease is made.


Instructions: Use the evaluation methods presented in class and reproduced here on this web page to help you learn how to evaluate a pulmonary function test report. Please try to determine if the patients represented in these ten (10) pulmonary function tests are normal, or if they have obstructive or restrictive disease. Also attempt to determine if they have mild, moderate or severe disease.


Pulmonary Function Test Problems

Case # 1.

Predicted Values
Measured Values
% Predicted
FVC
6.00 liters
4.00 liters
67 %
FEV1
5.00 liters
2.00 liters
40 %
FEV1/FVC
83 %
50 %
60 %

Decision : This person is : ______________________________

Case # 2.

Predicted Values
Measured Values
% Predicted
FVC
5.68 liters
4.43 liters
78 %
FEV1
4.90 liters
3.52 liters
72 %
FEV1/FVC
84 %
79 %
94 %

Decision : This person is ______________________________

Case # 3.

Predicted Values
Measured Values
% Predicted
FVC
5.04 liters
5.98 liters
119 %
FEV1
4.11 liters
4.58 liters
111 %
FEV1/FVC
82 %
77 %
94 %

Decision : This person is ______________________________

Case # 4.

Predicted Values
Measured Values
% Predicted
FVC
3.20 liters
2.78 liters
87 %
FEV1
2.51 liters
2.19 liters
87 %
FEV1/FVC
78 %
79 %
101 %

Decision : This person is ______________________________

Case # 5.

Predicted Values
Measured Values
% Predicted
FVC
3.20 liters
3.01 liters
94 %
FEV1
2.51 liters
1.19 liters
47 %
FEV1/FVC
78 %
39 %
50 %

Decision : This person is ______________________________

Case 6.

Predicted Values
Measured Values
% Predicted
FVC
4.80 liters
4.10 liters
85 %
FEV1
3.65 liters
3.10 liters
85 %
FEV1/FVC
76 %
76 %
100 %

Decision : This person is ______________________________

Case # 7.

Predicted Values
Measured Values
% Predicted
FVC
5.80 liters
4.98 liters
86 %
FEV1
4.70liters
4.38 liters
93 %
FEV1/FVC
81 %
88 %
109 %

Decision : This person is ______________________________

Case # 8.

Predicted Values
Measured Values
% Predicted
FVC
2.30 liters
1.88 liters
82 %
FEV1
1.65 liters
.7 liters
42 %
FEV1/FVC
72 %
37 %
51 %

Decision : This person is ______________________________

Case # 9.

Predicted Values
Measured Values
% Predicted
FVC
7.20 liters
6.01 liters
83 %
FEV1
6.45 liters
5.35 liters
83 %
FEV1/FVC
90 %
89 %
99 %

Decision : This person is ______________________________

Case 10.

Predicted Values
Measured Values
% Predicted
FVC
6.76 liters
4.78 liters
71 %
FEV1
5.00 liters
2.00 liters
40 %
FEV1/FVC
74 %
42 %
56 %

Decision : This person is ______________________________