CRT & RRT Respiratory Therapy
Certification Practice Exam Study Guide
2026 | Updated Questions & Answers
with Verified Rationales | NBRC Exam
Prep
• This 200-question practice exam mirrors the NBRC CRT & RRT certification format,
covering all high-yield respiratory therapy domains to prepare you for exam day
with confidence.
• Study tip: Attempt each question independently before checking the correct
answer and EXPERT RATIONALE — this active recall method maximizes retention
and identifies knowledge gaps efficiently.
1. A patient has a PaO₂ of 55 mmHg on room air. What is the correct
interpretation?
A. Normal oxygenation
B. Mild hypoxemia
C. Moderate hypoxemia
D. Severe hypoxemia
E. Hyperoxemia
CORRECT ANSWER: C. Moderate hypoxemia
EXPERT RATIONALE: A PaO₂ of 55 mmHg falls within the moderate hypoxemia
range (45–59 mmHg). Mild hypoxemia is 60–79 mmHg, severe is below 45 mmHg,
and normal PaO₂ is 80–100 mmHg on room air.
2. Which of the following arterial blood gas results indicates uncompensated
respiratory acidosis?
A. pH 7.50, PaCO₂ 30, HCO₃ 24
B. pH 7.35, PaCO₂ 45, HCO₃ 26
,C. pH 7.28, PaCO₂ 58, HCO₃ 24
D. pH 7.40, PaCO₂ 40, HCO₃ 24
E. pH 7.48, PaCO₂ 38, HCO₃ 30
CORRECT ANSWER: C. pH 7.28, PaCO₂ 58, HCO₃ 24
EXPERT RATIONALE: Uncompensated respiratory acidosis shows a low pH,
elevated PaCO₂, and a normal HCO₃ (no renal compensation has occurred yet). pH
7.28 is acidotic, PaCO₂ 58 is elevated, and HCO₃ 24 is within normal range.
3. A patient is receiving oxygen via nasal cannula at 4 L/min. What is the
approximate FiO₂ being delivered?
A. 24%
B. 28%
C. 36%
D. 40%
E. 44%
CORRECT ANSWER: C. 36%
EXPERT RATIONALE: With nasal cannula, each liter per minute adds
approximately 4% FiO₂ above room air (21%). At 4 L/min: 21 + (4 × 4) = 37%,
rounded clinically to 36%. This is the standard rule of thumb used on the NBRC
exam.
4. Which lung volume CANNOT be measured by spirometry alone?
A. Tidal volume
B. Inspiratory reserve volume
C. Expiratory reserve volume
D. Residual volume
,E. Vital capacity
CORRECT ANSWER: D. Residual volume
EXPERT RATIONALE: Residual volume (RV) is the air remaining in the lungs after
maximal exhalation and cannot be exhaled or measured by spirometry. It requires
body plethysmography, helium dilution, or nitrogen washout techniques.
5. The normal pH range for arterial blood is:
A. 7.25 – 7.35
B. 7.35 – 7.45
C. 7.40 – 7.50
D. 7.30 – 7.40
E. 7.45 – 7.55
CORRECT ANSWER: B. 7.35 – 7.45
EXPERT RATIONALE: Normal arterial blood pH ranges from 7.35 to 7.45. Values
below 7.35 indicate acidosis and above 7.45 indicate alkalosis. This is a foundational
value for ABG interpretation on the NBRC exam.
6. A patient presents with pink frothy sputum, severe dyspnea, and bilateral
crackles. What condition is most likely?
A. Pneumonia
B. Pulmonary embolism
C. Acute pulmonary edema
D. Asthma exacerbation
E. Spontaneous pneumothorax
CORRECT ANSWER: C. Acute pulmonary edema
, EXPERT RATIONALE: Pink frothy sputum is a classic hallmark of acute
pulmonary edema caused by fluid leaking into alveoli. Combined with bilateral
crackles and severe dyspnea, this presentation strongly indicates cardiogenic
pulmonary edema.
7. Which of the following is the primary muscle of inspiration?
A. External intercostals
B. Sternocleidomastoid
C. Diaphragm
D. Scalene muscles
E. Internal intercostals
CORRECT ANSWER: C. Diaphragm
EXPERT RATIONALE: The diaphragm is responsible for approximately 70–80%
of the work of breathing during normal quiet inspiration. It contracts and descends,
increasing thoracic volume and decreasing intrathoracic pressure, drawing air into
the lungs.
8. What is the normal tidal volume for an adult at rest?
A. 150 mL
B. 350 mL
C. 500 mL
D. 750 mL
E. 1000 mL
CORRECT ANSWER: C. 500 mL
Certification Practice Exam Study Guide
2026 | Updated Questions & Answers
with Verified Rationales | NBRC Exam
Prep
• This 200-question practice exam mirrors the NBRC CRT & RRT certification format,
covering all high-yield respiratory therapy domains to prepare you for exam day
with confidence.
• Study tip: Attempt each question independently before checking the correct
answer and EXPERT RATIONALE — this active recall method maximizes retention
and identifies knowledge gaps efficiently.
1. A patient has a PaO₂ of 55 mmHg on room air. What is the correct
interpretation?
A. Normal oxygenation
B. Mild hypoxemia
C. Moderate hypoxemia
D. Severe hypoxemia
E. Hyperoxemia
CORRECT ANSWER: C. Moderate hypoxemia
EXPERT RATIONALE: A PaO₂ of 55 mmHg falls within the moderate hypoxemia
range (45–59 mmHg). Mild hypoxemia is 60–79 mmHg, severe is below 45 mmHg,
and normal PaO₂ is 80–100 mmHg on room air.
2. Which of the following arterial blood gas results indicates uncompensated
respiratory acidosis?
A. pH 7.50, PaCO₂ 30, HCO₃ 24
B. pH 7.35, PaCO₂ 45, HCO₃ 26
,C. pH 7.28, PaCO₂ 58, HCO₃ 24
D. pH 7.40, PaCO₂ 40, HCO₃ 24
E. pH 7.48, PaCO₂ 38, HCO₃ 30
CORRECT ANSWER: C. pH 7.28, PaCO₂ 58, HCO₃ 24
EXPERT RATIONALE: Uncompensated respiratory acidosis shows a low pH,
elevated PaCO₂, and a normal HCO₃ (no renal compensation has occurred yet). pH
7.28 is acidotic, PaCO₂ 58 is elevated, and HCO₃ 24 is within normal range.
3. A patient is receiving oxygen via nasal cannula at 4 L/min. What is the
approximate FiO₂ being delivered?
A. 24%
B. 28%
C. 36%
D. 40%
E. 44%
CORRECT ANSWER: C. 36%
EXPERT RATIONALE: With nasal cannula, each liter per minute adds
approximately 4% FiO₂ above room air (21%). At 4 L/min: 21 + (4 × 4) = 37%,
rounded clinically to 36%. This is the standard rule of thumb used on the NBRC
exam.
4. Which lung volume CANNOT be measured by spirometry alone?
A. Tidal volume
B. Inspiratory reserve volume
C. Expiratory reserve volume
D. Residual volume
,E. Vital capacity
CORRECT ANSWER: D. Residual volume
EXPERT RATIONALE: Residual volume (RV) is the air remaining in the lungs after
maximal exhalation and cannot be exhaled or measured by spirometry. It requires
body plethysmography, helium dilution, or nitrogen washout techniques.
5. The normal pH range for arterial blood is:
A. 7.25 – 7.35
B. 7.35 – 7.45
C. 7.40 – 7.50
D. 7.30 – 7.40
E. 7.45 – 7.55
CORRECT ANSWER: B. 7.35 – 7.45
EXPERT RATIONALE: Normal arterial blood pH ranges from 7.35 to 7.45. Values
below 7.35 indicate acidosis and above 7.45 indicate alkalosis. This is a foundational
value for ABG interpretation on the NBRC exam.
6. A patient presents with pink frothy sputum, severe dyspnea, and bilateral
crackles. What condition is most likely?
A. Pneumonia
B. Pulmonary embolism
C. Acute pulmonary edema
D. Asthma exacerbation
E. Spontaneous pneumothorax
CORRECT ANSWER: C. Acute pulmonary edema
, EXPERT RATIONALE: Pink frothy sputum is a classic hallmark of acute
pulmonary edema caused by fluid leaking into alveoli. Combined with bilateral
crackles and severe dyspnea, this presentation strongly indicates cardiogenic
pulmonary edema.
7. Which of the following is the primary muscle of inspiration?
A. External intercostals
B. Sternocleidomastoid
C. Diaphragm
D. Scalene muscles
E. Internal intercostals
CORRECT ANSWER: C. Diaphragm
EXPERT RATIONALE: The diaphragm is responsible for approximately 70–80%
of the work of breathing during normal quiet inspiration. It contracts and descends,
increasing thoracic volume and decreasing intrathoracic pressure, drawing air into
the lungs.
8. What is the normal tidal volume for an adult at rest?
A. 150 mL
B. 350 mL
C. 500 mL
D. 750 mL
E. 1000 mL
CORRECT ANSWER: C. 500 mL
