CPFT Certification Exam 2026: Comprehensive Certified Pulmonary
Function Technologist Practice Test — Pulmonary Function Testing,
Spirometry, Lung Volumes, Gas Exchange, Patient Assessment &
Quality Control — 190 Multiple-Choice Questions with Answers &
Detailed Rationales
DOMAIN I: INSTRUMENTATION / EQUIPMENT (57 Questions)
Question 1
A pulmonary function technologist is preparing a spirometer for daily use. Which of the
following represents the primary purpose of calibration verification?
A. To increase the speed of test performance
B. To ensure the device provides accurate and reliable measurements
C. To reduce patient discomfort during testing
D. To comply with insurance billing requirements
Correct Answer: B
Explanation: Calibration verifies that the spirometer accurately measures known volumes,
ensuring valid clinical data. Without proper calibration, test results may lead to incorrect
diagnosis or management decisions.
Question 2
Which of the following volume-sensing spirometers uses a water-seal mechanism to
measure exhaled volumes?
A. Turbine spirometer
B. Ultrasonic spirometer
,C. Water-seal spirometer
D. Pneumotachometer
Correct Answer: C
Explanation: A water-seal spirometer uses a water-filled chamber and floating bell to
measure exhaled volumes, historically considered the gold standard for accuracy.
Question 3
When calibrating a flow-sensing turbine spirometer, which parameter is most critical to
verify?
A. Temperature stability
B. Volume accuracy across a range of flow rates
C. Barometric pressure
D. Gas composition
Correct Answer: B
Explanation: Turbine devices measure flow and derive volume by integration; therefore,
accuracy at various flow rates must be confirmed using a 3-liter syringe at different speeds.
Question 4
A technologist notices that a spirometer's calibration syringe produces volumes consistently
5% below the expected 3.00 liters. What is the most appropriate initial action?
A. Continue testing and note the discrepancy in the report
,B. Recalibrate the spirometer according to manufacturer specifications
C. Replace the calibration syringe
D. Refer the patient to another laboratory
Correct Answer: B
Explanation: A consistent volume discrepancy indicates the spirometer requires
recalibration; testing should not proceed until accuracy is restored. The calibration syringe is
a fixed-volume device unlikely to be the source of error.
Question 5
Which of the following is the most common method for disinfecting reusable pulmonary
function testing equipment?
A. Autoclaving at 121°C
B. Chemical disinfection with glutaraldehyde or accelerated hydrogen peroxide
C. Ultraviolet light exposure
D. Dry heat sterilization
Correct Answer: B
Explanation: Chemical disinfection using agents such as glutaraldehyde or accelerated
hydrogen peroxide is standard for PFT equipment, as autoclaving may damage sensitive
components.
Question 6
A technologist is setting up a body plethysmograph. Which of the following components is
essential for measuring thoracic gas volume?
, A. A 3-liter calibration syringe
B. A pressure transducer and shutter mechanism
C. A helium analyzer
D. A carbon monoxide detector
Correct Answer: B
Explanation: Body plethysmography measures thoracic gas volume using a pressure
transducer to detect changes in box pressure against a closed shutter, applying Boyle's law.
Question 7
Which of the following gas analyzers is used for measuring static lung volumes by gas
dilution?
A. Carbon monoxide analyzer
B. Helium analyzer
C. Pulse oximeter
D. Capnograph
Correct Answer: B
Explanation: Helium dilution is a common method for measuring functional residual capacity
and static lung volumes; the helium analyzer detects gas concentration changes during
rebreathing.
Question 8
Function Technologist Practice Test — Pulmonary Function Testing,
Spirometry, Lung Volumes, Gas Exchange, Patient Assessment &
Quality Control — 190 Multiple-Choice Questions with Answers &
Detailed Rationales
DOMAIN I: INSTRUMENTATION / EQUIPMENT (57 Questions)
Question 1
A pulmonary function technologist is preparing a spirometer for daily use. Which of the
following represents the primary purpose of calibration verification?
A. To increase the speed of test performance
B. To ensure the device provides accurate and reliable measurements
C. To reduce patient discomfort during testing
D. To comply with insurance billing requirements
Correct Answer: B
Explanation: Calibration verifies that the spirometer accurately measures known volumes,
ensuring valid clinical data. Without proper calibration, test results may lead to incorrect
diagnosis or management decisions.
Question 2
Which of the following volume-sensing spirometers uses a water-seal mechanism to
measure exhaled volumes?
A. Turbine spirometer
B. Ultrasonic spirometer
,C. Water-seal spirometer
D. Pneumotachometer
Correct Answer: C
Explanation: A water-seal spirometer uses a water-filled chamber and floating bell to
measure exhaled volumes, historically considered the gold standard for accuracy.
Question 3
When calibrating a flow-sensing turbine spirometer, which parameter is most critical to
verify?
A. Temperature stability
B. Volume accuracy across a range of flow rates
C. Barometric pressure
D. Gas composition
Correct Answer: B
Explanation: Turbine devices measure flow and derive volume by integration; therefore,
accuracy at various flow rates must be confirmed using a 3-liter syringe at different speeds.
Question 4
A technologist notices that a spirometer's calibration syringe produces volumes consistently
5% below the expected 3.00 liters. What is the most appropriate initial action?
A. Continue testing and note the discrepancy in the report
,B. Recalibrate the spirometer according to manufacturer specifications
C. Replace the calibration syringe
D. Refer the patient to another laboratory
Correct Answer: B
Explanation: A consistent volume discrepancy indicates the spirometer requires
recalibration; testing should not proceed until accuracy is restored. The calibration syringe is
a fixed-volume device unlikely to be the source of error.
Question 5
Which of the following is the most common method for disinfecting reusable pulmonary
function testing equipment?
A. Autoclaving at 121°C
B. Chemical disinfection with glutaraldehyde or accelerated hydrogen peroxide
C. Ultraviolet light exposure
D. Dry heat sterilization
Correct Answer: B
Explanation: Chemical disinfection using agents such as glutaraldehyde or accelerated
hydrogen peroxide is standard for PFT equipment, as autoclaving may damage sensitive
components.
Question 6
A technologist is setting up a body plethysmograph. Which of the following components is
essential for measuring thoracic gas volume?
, A. A 3-liter calibration syringe
B. A pressure transducer and shutter mechanism
C. A helium analyzer
D. A carbon monoxide detector
Correct Answer: B
Explanation: Body plethysmography measures thoracic gas volume using a pressure
transducer to detect changes in box pressure against a closed shutter, applying Boyle's law.
Question 7
Which of the following gas analyzers is used for measuring static lung volumes by gas
dilution?
A. Carbon monoxide analyzer
B. Helium analyzer
C. Pulse oximeter
D. Capnograph
Correct Answer: B
Explanation: Helium dilution is a common method for measuring functional residual capacity
and static lung volumes; the helium analyzer detects gas concentration changes during
rebreathing.
Question 8
