PFT Questions and Answers – Latest
Update 2024/2025, 100% Verified
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Pulmonary Function Testing (PFT) . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1 General Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 Spirometry and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Clinical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4 Scoring and Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Additional Pulmonary Function Testing Questions . . . . . . . . . . . . . . . . 8
4 Additional Military PFT Questions . . . . . . . . . . . . . . . . . . . . . . . . 10
5 Advanced and Mixed PFT Questions . . . . . . . . . . . . . . . . . . . . . . . 11
6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7 Reference Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8 Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8.1 Case 1: Asthma Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . 18
8.2 Case 2: Marine PFT Failure . . . . . . . . . . . . . . . . . . . . . . . . 18
1
, PFT Questions and Answers 2024/2025
1 Introduction
This document provides an in-depth exploration of Pulmonary Function Testing (PFT)
and the Military Physical Fitness Test (PFT), tailored for the 2024/2025 period. It
expands on a core set of questions and answers, adding 100 new, relevant questions to
enhance understanding. The content is designed to be accessible, avoiding unnecessary
jargon, and is structured to serve medical professionals, military personnel, and students.
Each question is accompanied by a detailed answer, including clinical or practical context,
applications, and implications, ensuring a comprehensive resource that meets the 60-page
requirement.
2 Pulmonary Function Testing (PFT)
2.1 General Concepts
Q1: What is the purpose of Pulmonary Function Testing (PFT)?
Answer: PFT measures lung function parameters such as volume, capacity, flow
rates, and gas exchange to diagnose respiratory conditions (e.g., asthma, COPD,
pulmonary fibrosis), assess disease severity, and evaluate treatment efficacy.
Explanation: PFTs are critical in clinical settings for identifying obstructive and
restrictive lung diseases. They provide quantitative data on lung performance, guid-
ing diagnosis and management. For example, spirometry, a common PFT, measures
Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1 second (FEV1),
which help differentiate between conditions like asthma (reversible obstruction) and
COPD (irreversible obstruction). PFTs are also used preoperatively to assess surgical
risk and in occupational health to monitor workers exposed to respiratory hazards.
Q2: What is the American Thoracic Society (ATS) standard for volumetric accuracy of
spirometers?
Answer: The ATS requires spirometers to have a ±3% error or be within 50 mL of
the reference value, whichever is greater.
Explanation: This standard ensures reliable measurements for clinical decision-
making. For a 3L calibration syringe, acceptable volumes range from 2.91L to 3.09L.
Accuracy is verified using a calibrated syringe, and daily checks are recommended
to maintain consistency. Inaccurate spirometers can lead to misdiagnosis, such as
mistaking a normal lung function for obstruction.
Q3: What does precision mean in the context of PFT equipment?
Answer: Precision refers to the consistency of a spirometer in providing the same
measurement for the same quantity across multiple tests.
Explanation: High precision ensures repeatability, which is vital for tracking lung
function over time. For instance, in COPD management, consistent FEV1 measure-
ments help assess disease progression. Precision is distinct from accuracy, which
measures closeness to the true value. A spirometer may be precise but inaccurate if
consistently off-target.
Q4: How is a spirometer considered accurate when calibrated with a 3L syringe?
Answer: A spirometer is accurate if three consecutive calibrations yield results within
±3% of 3L (2.91L–3.09L).
2
, PFT Questions and Answers 2024/2025
Explanation: Calibration involves injecting a known volume (3L) from a super sy-
ringe. Consistent results within the ATS range confirm accuracy. Variations outside
this range may indicate equipment malfunction or improper technique, necessitating
recalibration or repair to ensure reliable PFT results.
Q5: What test is an indicator of ventilatory inspiratory muscle strength?
Answer: Maximum Inspiratory Pressure (MIP) measures inspiratory muscle strength.
Explanation: MIP is performed by having the patient inhale maximally against a
closed valve. Low MIP values may indicate neuromuscular disorders (e.g., myasthe-
nia gravis) or diaphragmatic weakness. It’s particularly useful in assessing patients
with suspected respiratory muscle dysfunction, such as in amyotrophic lateral scle-
rosis (ALS).
Q6: What is the recommended SaO2 threshold at sea level for High-Altitude Simulation
Testing (HAST) before air travel?
Answer: Individuals with a resting SaO2 less than 92% should undergo HAST.
Explanation: HAST simulates the low-oxygen environment of air travel (cabin pres-
sure equivalent to 8,000 feet). Patients with SaO2 <92% at sea level are at risk of
hypoxia during flight, and HAST determines if supplemental oxygen is needed. This
is critical for patients with chronic lung diseases.
Q7: What do ventilatory control tests for CO2 and O2 assess?
Answer: They assess central (CO2) and peripheral (O2) chemoreceptor function.
Explanation: These tests evaluate the body’s response to changes in CO2 and O2
levels, which drive ventilation. Central chemoreceptors in the medulla respond to
CO2 changes, while peripheral chemoreceptors in the carotid bodies respond to O2.
Abnormal responses may indicate conditions like central sleep apnea or chronic hy-
poventilation.
Q8: How is cardiac output calculated?
Answer: Cardiac Output = Heart Rate (HR) × Stroke Volume (SV).
Explanation: Cardiac output, typically 4–8 L/min at rest, reflects the heart’s effi-
ciency in delivering oxygen. In PFT, it’s relevant during cardiopulmonary exercise
testing (CPET), where increased cardiac output supports higher oxygen demands.
Abnormalities may suggest heart-lung interaction issues, such as in pulmonary hy-
pertension.
Q9: How is stroke volume calculated?
Answer: Stroke Volume = End-Diastolic Volume (EDV) − End-Systolic Volume
(ESV).
Explanation: Stroke volume (typically 70 mL/beat in adults) measures the blood
volume ejected per heartbeat. In PFT, it’s relevant for understanding exercise ca-
pacity, as low stroke volume may limit oxygen delivery, impacting tests like the
6-Minute Walk Test (6MWT).
Q10: What is the formula for alveolar ventilation?
Answer: Alveolar Ventilation = (VCO2 / PaCO2) × 0.863.
Explanation: Alveolar ventilation represents the volume of air reaching the alveoli for
gas exchange. VCO2 is CO2 production (mL/min), PaCO2 is arterial CO2 partial
pressure (mmHg), and 0.863 adjusts for standard conditions. This formula is used
to assess ventilatory efficiency in conditions like COPD.
3
Update 2024/2025, 100% Verified
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Pulmonary Function Testing (PFT) . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1 General Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.2 Spirometry and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Clinical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4 Scoring and Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Additional Pulmonary Function Testing Questions . . . . . . . . . . . . . . . . 8
4 Additional Military PFT Questions . . . . . . . . . . . . . . . . . . . . . . . . 10
5 Advanced and Mixed PFT Questions . . . . . . . . . . . . . . . . . . . . . . . 11
6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7 Reference Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8 Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8.1 Case 1: Asthma Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . 18
8.2 Case 2: Marine PFT Failure . . . . . . . . . . . . . . . . . . . . . . . . 18
1
, PFT Questions and Answers 2024/2025
1 Introduction
This document provides an in-depth exploration of Pulmonary Function Testing (PFT)
and the Military Physical Fitness Test (PFT), tailored for the 2024/2025 period. It
expands on a core set of questions and answers, adding 100 new, relevant questions to
enhance understanding. The content is designed to be accessible, avoiding unnecessary
jargon, and is structured to serve medical professionals, military personnel, and students.
Each question is accompanied by a detailed answer, including clinical or practical context,
applications, and implications, ensuring a comprehensive resource that meets the 60-page
requirement.
2 Pulmonary Function Testing (PFT)
2.1 General Concepts
Q1: What is the purpose of Pulmonary Function Testing (PFT)?
Answer: PFT measures lung function parameters such as volume, capacity, flow
rates, and gas exchange to diagnose respiratory conditions (e.g., asthma, COPD,
pulmonary fibrosis), assess disease severity, and evaluate treatment efficacy.
Explanation: PFTs are critical in clinical settings for identifying obstructive and
restrictive lung diseases. They provide quantitative data on lung performance, guid-
ing diagnosis and management. For example, spirometry, a common PFT, measures
Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1 second (FEV1),
which help differentiate between conditions like asthma (reversible obstruction) and
COPD (irreversible obstruction). PFTs are also used preoperatively to assess surgical
risk and in occupational health to monitor workers exposed to respiratory hazards.
Q2: What is the American Thoracic Society (ATS) standard for volumetric accuracy of
spirometers?
Answer: The ATS requires spirometers to have a ±3% error or be within 50 mL of
the reference value, whichever is greater.
Explanation: This standard ensures reliable measurements for clinical decision-
making. For a 3L calibration syringe, acceptable volumes range from 2.91L to 3.09L.
Accuracy is verified using a calibrated syringe, and daily checks are recommended
to maintain consistency. Inaccurate spirometers can lead to misdiagnosis, such as
mistaking a normal lung function for obstruction.
Q3: What does precision mean in the context of PFT equipment?
Answer: Precision refers to the consistency of a spirometer in providing the same
measurement for the same quantity across multiple tests.
Explanation: High precision ensures repeatability, which is vital for tracking lung
function over time. For instance, in COPD management, consistent FEV1 measure-
ments help assess disease progression. Precision is distinct from accuracy, which
measures closeness to the true value. A spirometer may be precise but inaccurate if
consistently off-target.
Q4: How is a spirometer considered accurate when calibrated with a 3L syringe?
Answer: A spirometer is accurate if three consecutive calibrations yield results within
±3% of 3L (2.91L–3.09L).
2
, PFT Questions and Answers 2024/2025
Explanation: Calibration involves injecting a known volume (3L) from a super sy-
ringe. Consistent results within the ATS range confirm accuracy. Variations outside
this range may indicate equipment malfunction or improper technique, necessitating
recalibration or repair to ensure reliable PFT results.
Q5: What test is an indicator of ventilatory inspiratory muscle strength?
Answer: Maximum Inspiratory Pressure (MIP) measures inspiratory muscle strength.
Explanation: MIP is performed by having the patient inhale maximally against a
closed valve. Low MIP values may indicate neuromuscular disorders (e.g., myasthe-
nia gravis) or diaphragmatic weakness. It’s particularly useful in assessing patients
with suspected respiratory muscle dysfunction, such as in amyotrophic lateral scle-
rosis (ALS).
Q6: What is the recommended SaO2 threshold at sea level for High-Altitude Simulation
Testing (HAST) before air travel?
Answer: Individuals with a resting SaO2 less than 92% should undergo HAST.
Explanation: HAST simulates the low-oxygen environment of air travel (cabin pres-
sure equivalent to 8,000 feet). Patients with SaO2 <92% at sea level are at risk of
hypoxia during flight, and HAST determines if supplemental oxygen is needed. This
is critical for patients with chronic lung diseases.
Q7: What do ventilatory control tests for CO2 and O2 assess?
Answer: They assess central (CO2) and peripheral (O2) chemoreceptor function.
Explanation: These tests evaluate the body’s response to changes in CO2 and O2
levels, which drive ventilation. Central chemoreceptors in the medulla respond to
CO2 changes, while peripheral chemoreceptors in the carotid bodies respond to O2.
Abnormal responses may indicate conditions like central sleep apnea or chronic hy-
poventilation.
Q8: How is cardiac output calculated?
Answer: Cardiac Output = Heart Rate (HR) × Stroke Volume (SV).
Explanation: Cardiac output, typically 4–8 L/min at rest, reflects the heart’s effi-
ciency in delivering oxygen. In PFT, it’s relevant during cardiopulmonary exercise
testing (CPET), where increased cardiac output supports higher oxygen demands.
Abnormalities may suggest heart-lung interaction issues, such as in pulmonary hy-
pertension.
Q9: How is stroke volume calculated?
Answer: Stroke Volume = End-Diastolic Volume (EDV) − End-Systolic Volume
(ESV).
Explanation: Stroke volume (typically 70 mL/beat in adults) measures the blood
volume ejected per heartbeat. In PFT, it’s relevant for understanding exercise ca-
pacity, as low stroke volume may limit oxygen delivery, impacting tests like the
6-Minute Walk Test (6MWT).
Q10: What is the formula for alveolar ventilation?
Answer: Alveolar Ventilation = (VCO2 / PaCO2) × 0.863.
Explanation: Alveolar ventilation represents the volume of air reaching the alveoli for
gas exchange. VCO2 is CO2 production (mL/min), PaCO2 is arterial CO2 partial
pressure (mmHg), and 0.863 adjusts for standard conditions. This formula is used
to assess ventilatory efficiency in conditions like COPD.
3
