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100+ Free RPFT Practice Questions

Pass your NBRC Registered Pulmonary Function Technologist exam on the first try — instant access, no signup required.

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Which of the following measurements requires the patient to be seated in a sealed, airtight chamber?

A
B
C
D
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2026 Statistics

Key Facts: RPFT Exam

115

Total Questions

NBRC (100 scored + 15 pilot)

2 hrs

Exam Time

NBRC candidate handbook

High Cut

Passing Score

NBRC scaled scoring model

$200

Exam Fee

NBRC fee schedule (2026)

5 yrs

Credential Validity

NBRC CMP renewal cycle

44%

Procedures Weight

NBRC PFT content outline

The NBRC PFT Examination uses 115 total items (100 scored + 15 pilot) with a 2-hour time limit and $200 fee. Two credential levels are awarded from the same exam: CPFT (low cut score) and RPFT (high cut score). Content weighting is Instrumentation/Equipment (33 scored items, 33%), Procedures (44 scored items, 44%), and Data Management (23 scored items, 23%). AARC members receive a one-time $40 discount on the initial application fee.

Sample RPFT Practice Questions

Try these sample questions to test your RPFT exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A spirometer is being calibrated using a 3-liter calibration syringe. The spirometer reads 2.88 liters on three consecutive trials. What is the most appropriate action?
A.Continue testing because the error is within acceptable limits
B.Replace the calibration syringe immediately
C.Adjust the spirometer calibration factor before testing
D.Report the spirometer as defective and remove it from service
Explanation: ATS/ERS standards require spirometer accuracy within ±3% of a known volume (3.0 L ± 0.090 L = 2.91–3.09 L). A reading of 2.88 L falls outside this range, so the calibration factor must be adjusted before patient testing. Simply continuing would yield inaccurate results, but the instrument is not necessarily defective—it just needs recalibration.
2Which of the following is the primary purpose of a body plethysmograph in pulmonary function testing?
A.Measuring diffusion capacity of the lungs
B.Measuring thoracic gas volume and airway resistance
C.Assessing exercise capacity during cardiopulmonary stress testing
D.Evaluating arterial blood gas values
Explanation: A body plethysmograph (body box) uses Boyle's law to measure thoracic gas volume (TGV), functional residual capacity (FRC), and airway resistance (Raw). Unlike gas dilution methods, it measures all intrathoracic gas, including trapped gas behind closed airways. This makes it the gold standard for static lung volume measurement.
3During a nitrogen washout test for FRC measurement, which of the following would most likely cause an erroneously high result?
A.A leak in the breathing circuit
B.The patient breathing room air instead of 100% oxygen
C.The nitrogen analyzer reading lower than actual values
D.The patient performing shallow breathing throughout the test
Explanation: A leak in the breathing circuit during a nitrogen washout test allows room air (78% nitrogen) to enter the system, contaminating the washout. This adds extraneous nitrogen that the analyzer attributes to lung volume, producing a falsely elevated FRC measurement. The test relies on a completely closed system to accurately measure the nitrogen washed out from the lungs.
4Which gas is used as the tracer in the single-breath diffusion capacity (DLCO) test?
A.Helium
B.Nitrogen
C.Carbon monoxide
D.Oxygen
Explanation: The single-breath DLCO test uses carbon monoxide (CO) as the tracer gas because CO has an extremely high affinity for hemoglobin (approximately 210 times that of oxygen). This means that essentially all CO that crosses the alveolar-capillary membrane binds to hemoglobin, making the partial pressure of CO in pulmonary capillary blood approximately zero and simplifying the diffusion calculation.
5A PFT lab is performing quality control on a blood gas analyzer. The control sample results fall outside the ±2 standard deviation (SD) range. What should the technologist do FIRST?
A.Run patient samples and flag the results as potentially inaccurate
B.Repeat the control sample to confirm the out-of-range result
C.Replace all electrodes in the blood gas analyzer
D.Notify the laboratory director and discontinue all testing
Explanation: When a quality control result falls outside the acceptable range (±2 SD), the first step is to repeat the control to determine whether the out-of-range result is a random error or a systematic problem. Running patient samples on an analyzer that has failed QC is not acceptable. Replacing electrodes or discontinuing testing entirely are premature steps before confirming the problem.
6A helium dilution test for measuring FRC yields a significantly lower value than a body plethysmography test performed on the same patient. Which condition best explains this discrepancy?
A.Pulmonary fibrosis with restrictive disease
B.Severe emphysema with air trapping
C.Healthy lungs with normal ventilation
D.Mild asthma in remission
Explanation: In severe emphysema with air trapping, gas dilution methods (helium dilution, nitrogen washout) underestimate FRC because trapped gas behind closed airways does not communicate with the inhaled tracer gas. Body plethysmography, which measures all compressible gas in the thorax using Boyle's law, captures the trapped gas volume. The difference between plethysmographic and dilution FRC is a measure of trapped gas volume.
7When performing spirometry, a patient's FVC maneuver shows a plateau on the volume-time curve but the expiratory time is only 4 seconds. According to ATS/ERS standards, what should the technologist do?
A.Accept the maneuver because a plateau was achieved
B.Reject the maneuver because the expiratory time must be at least 6 seconds
C.Accept the maneuver because a plateau with stable volume indicates adequate effort
D.Repeat the maneuver and have the patient blow for at least 15 seconds
Explanation: According to ATS/ERS 2019 spirometry standards, an acceptable FVC maneuver requires either a volume-time plateau (no change in volume >0.025 L for ≥1 second) OR an expiratory time of ≥15 seconds. If a clear plateau is reached before 6 seconds, the maneuver can still be accepted. The plateau criterion takes precedence over a minimum expiratory time, as it indicates complete exhalation.
8During a cardiopulmonary exercise test (CPET), the patient's ventilatory equivalent for oxygen (VE/VO2) reaches its nadir and then begins to rise while VE/VCO2 continues to decrease. This point represents the:
A.Respiratory compensation point
B.Anaerobic threshold (ventilatory threshold 1)
C.Peak exercise capacity
D.Lactate clearance point
Explanation: The anaerobic threshold (AT), also known as ventilatory threshold 1 (VT1), is identified during CPET as the point where VE/VO2 begins to rise systematically while VE/VCO2 remains stable or continues to decrease. This occurs because increased CO2 production from lactate buffering drives ventilation up relative to O2 consumption. The V-slope method (VCO2 vs. VO2) is another common way to identify this threshold.
9Which of the following is the correct breath-hold time for a standard single-breath DLCO test according to ATS/ERS guidelines?
A.5 ± 1 seconds
B.10 ± 2 seconds
C.15 ± 3 seconds
D.20 ± 2 seconds
Explanation: The ATS/ERS standard for single-breath DLCO testing specifies a breath-hold time of 10 ± 2 seconds (8–12 seconds). The Jones-Meade method is used to calculate the breath-hold time, measured from when two-thirds of the inspired volume has been inhaled to the beginning of the alveolar gas sample collection. Breath-hold times outside this range can significantly affect DLCO results.
10A patient's arterial blood gas results show: pH 7.28, PaCO2 55 mmHg, HCO3 26 mEq/L, PaO2 58 mmHg. How should these results be interpreted?
A.Compensated metabolic acidosis with hypoxemia
B.Acute respiratory acidosis with hypoxemia
C.Chronic respiratory acidosis with adequate compensation
D.Mixed respiratory and metabolic acidosis
Explanation: The elevated PaCO2 (55 mmHg, normal 35–45) indicates respiratory acidosis. The pH is significantly low (7.28), and the HCO3 is only slightly above normal (26 mEq/L, normal 22–26), indicating that renal compensation has not yet occurred. In chronic respiratory acidosis, HCO3 would be significantly elevated (approximately 3.5 mEq/L increase per 10 mmHg PaCO2 rise). The PaO2 of 58 mmHg confirms hypoxemia.

About the RPFT Exam

The RPFT credential from the National Board for Respiratory Care demonstrates advanced expertise in pulmonary function testing. The PFT Examination covers instrumentation and equipment (setup, calibration, troubleshooting, QC), clinical testing procedures (spirometry, lung volumes, DLCO, exercise testing), and data management (calculation, interpretation, reference ranges). Earning the RPFT requires achieving the high cut score on the PFT Examination.

Questions

100 scored questions

Time Limit

2 hours

Passing Score

High cut score (scaled)

Exam Fee

$200 (NBRC)

RPFT Exam Content Outline

33 scored (33%)

Instrumentation and Equipment

Setup, maintenance, calibration, troubleshooting of spirometers, plethysmographs, gas analyzers, blood gas systems, and quality control procedures

44 scored (44%)

Procedures

Test protocol selection, spirometry, lung volumes, DLCO, exercise testing, bronchoprovocation, oxygen titration, and result validity evaluation

23 scored (23%)

Data Management

Result calculation, BTPS corrections, reference range selection, reliability evaluation, interpretation, and clinical reporting

How to Pass the RPFT Exam

What You Need to Know

  • Passing score: High cut score (scaled)
  • Exam length: 100 questions
  • Time limit: 2 hours
  • Exam fee: $200

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

RPFT Study Tips from Top Performers

1Prioritize the Procedures domain (44% of exam): spirometry technique, lung volumes, DLCO, exercise testing, and bronchoprovocation
2Master ATS/ERS spirometry standards including acceptability criteria, repeatability, and quality grading
3Practice blood gas interpretation systematically: identify primary disorder, check compensation, calculate A-a gradient
4Know body plethysmography principles (Boyle's law) and how trapped gas causes differences from gas dilution methods
5Review equipment troubleshooting scenarios—calibration drift, analyzer errors, and QC failure response protocols

Frequently Asked Questions

How many questions are on the RPFT exam?

The PFT Examination contains 115 total questions: 100 scored items plus 15 pilot (unscored) items. You will not know which questions are pilot items.

What is the time limit for the RPFT exam?

The PFT Examination has a 2-hour (120-minute) time limit to complete all 115 questions.

What score do I need to earn the RPFT credential?

The RPFT credential requires achieving the high cut score on the PFT Examination. NBRC uses scaled scoring with two cut points: the low cut score earns CPFT, and the high cut score earns RPFT.

How much does the RPFT exam cost?

The PFT Examination fee is $200 for new applicants and $170 for repeat applicants. AARC members receive a one-time $40 discount on the initial fee.

What are the prerequisites for the RPFT exam?

You must be 18+ and meet one eligibility pathway: hold the CPFT credential, OR complete 62 semester hours of college credit (including biology, chemistry, and math) with 6 months of PFT experience.

How should I prepare for the RPFT exam in 2026?

Focus on procedures (44% of scored items) and instrumentation (33%), then master data management and interpretation. Practice ABG analysis, flow-volume loop interpretation, and equipment troubleshooting scenarios daily.