MCCQE Part I Pulmonary embolism Questions: 10 Free Practice MCQs
Ten MCCQE Part I-style pulmonary embolism questions with the answer and the reasoning behind it. They come from the CA.med bank, which has 40 pulmonary embolism questions and many more across every topic.
1 / 10
A 71-year-old with suspected PE has D-dimer 900 mcg/L and low probability. The clinician records vital signs and estimates pretest probability before testing.
What is the age adjusted interpretation?
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Answer: C. It is positive: age 71 gives a cutoff of 710 mcg/L, and 900 mcg/L warrants imaging.
Why: Age adjustment raises the cutoff to age multiplied by 10 mcg/L for patients at least 50 years old. D-dimer is not diagnostic by itself, so a positive result leads to imaging rather than automatic treatment. The tempting alternative, Apply the standard 500 mcg/L cutoff and classify 900 as negative because the patient is elderly, does not change the next step: the age-adjusted FEU threshold is 710 mcg/L at age 71; 900 is above it and calls for imaging.
- A. Choosing “Apply the standard 500 mcg/L cutoff and classify 900 as negative because the patient is elderly.” would lead to the wrong next step here because the age-adjusted FEU threshold is 710 mcg/L at age 71; 900 is above it and calls for imaging.
- B. Choosing “Use an age-adjusted threshold of 1000 mcg/L for anyone over 70, so no imaging is needed.” would lead to the wrong next step here because the age-adjusted FEU threshold is 710 mcg/L at age 71; 900 is above it and calls for imaging.
- D. Choosing “Diagnose PE from the elevated D-dimer and start treatment without imaging.” would lead to the wrong next step here because the age-adjusted FEU threshold is 710 mcg/L at age 71; 900 is above it and calls for imaging.
Sources: Thrombosis Canada Clinical Guide, Pulmonary Embolism Diagnosis, version 30 April 2025
2 / 10
A 24-year-old has low clinical probability and meets every PERC criterion. The clinician records vital signs and estimates pretest probability before testing.
What testing is needed?
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Answer: A. No further PE testing is indicated once clinical probability is low and all eight PERC criteria are negative.
Why: PERC is used only after low clinical probability is established, and all criteria must be negative to avoid testing. Ordering D-dimer or imaging after a negative PERC screen adds false positives and radiation without improving this patient’s assessment. The tempting alternative, Order bilateral leg ultrasound first and scan the chest only if a proximal clot is found, does not change the next step: with low pretest probability and every PERC criterion negative, the post-test risk is low enough to stop without D-dimer or imaging.
- B. Choosing “Order a high-sensitivity D-dimer now, then obtain CTPA if it exceeds 500 mcg/L.” would lead to the wrong next step here because with low pretest probability and every PERC criterion negative, the post-test risk is low enough to stop without D-dimer or imaging.
- C. Choosing “Proceed directly to CTPA because a normal examination cannot exclude a small embolus.” would lead to the wrong next step here because with low pretest probability and every PERC criterion negative, the post-test risk is low enough to stop without D-dimer or imaging.
- D. Choosing “Order bilateral leg ultrasound first and scan the chest only if a proximal clot is found.” would lead to the wrong next step here because with low pretest probability and every PERC criterion negative, the post-test risk is low enough to stop without D-dimer or imaging.
Sources: Thrombosis Canada Clinical Guide, Pulmonary Embolism Diagnosis, version 30 April 2025
3 / 10
A 44-year-old with low probability has a sensitive D-dimer of 430 mcg/L. The clinician records vital signs and estimates pretest probability before testing.
How should this result be interpreted?
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Answer: C. A sensitive D-dimer of 430 mcg/L is below the 500 mcg/L cutoff and excludes PE at low probability.
Why: A negative sensitive D-dimer can exclude PE when pretest probability is low or moderate. The YEARS threshold of 1000 mcg/L is a separate validated pathway and should not be substituted without applying its criteria. The tempting alternative, Obtain CTPA despite the negative result because D-dimer is not useful in low probability, does not change the next step: at age 44, the standard sensitive-assay cutoff is 500 mcg/L; 430 is negative in this low-probability evaluation.
- A. Choosing “Treat 430 mcg/L as positive because any detectable D-dimer indicates active thrombosis.” would lead to the wrong next step here because at age 44, the standard sensitive-assay cutoff is 500 mcg/L; 430 is negative in this low-probability evaluation.
- B. Choosing “Use a 1000 mcg/L cutoff because the patient is younger than 50.” would lead to the wrong next step here because at age 44, the standard sensitive-assay cutoff is 500 mcg/L; 430 is negative in this low-probability evaluation.
- D. Choosing “Obtain CTPA despite the negative result because D-dimer is not useful in low probability.” would lead to the wrong next step here because at age 44, the standard sensitive-assay cutoff is 500 mcg/L; 430 is negative in this low-probability evaluation.
Sources: Thrombosis Canada Clinical Guide, Pulmonary Embolism Diagnosis, version 30 April 2025
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4 / 10
A 32-year-old with moderate probability has D-dimer 490 mcg/L. The clinician records vital signs and estimates pretest probability before testing.
What does this result support?
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Answer: D. A sensitive D-dimer of 490 mcg/L is below 500 mcg/L and excludes PE at moderate probability.
Why: A negative sensitive D-dimer excludes PE in low or moderate probability when the standard cutoff pathway is used. The 1000 mcg/L YEARS threshold is appropriate only when no YEARS criteria are present and that pathway is deliberately applied. The tempting alternative, Repeat D-dimer in 24 hours to see whether the value rises above the laboratory cutoff, does not change the next step: for a 32-year-old on the standard sensitive-assay pathway, 490 mcg/L is below the 500 mcg/L threshold.
- A. Choosing “Use 1000 mcg/L as the cutoff for every patient without hemoptysis.” would lead to the wrong next step here because for a 32-year-old on the standard sensitive-assay pathway, 490 mcg/L is below the 500 mcg/L threshold.
- B. Choosing “Interpret 490 mcg/L as positive and obtain CTPA because the probability is moderate.” would lead to the wrong next step here because for a 32-year-old on the standard sensitive-assay pathway, 490 mcg/L is below the 500 mcg/L threshold.
- C. Choosing “Repeat D-dimer in 24 hours to see whether the value rises above the laboratory cutoff.” would lead to the wrong next step here because for a 32-year-old on the standard sensitive-assay pathway, 490 mcg/L is below the 500 mcg/L threshold.
Sources: Thrombosis Canada Clinical Guide, Pulmonary Embolism Diagnosis, version 30 April 2025
5 / 10
A 58-year-old has a D-dimer of 590 mcg/L and low probability. The clinician records vital signs and estimates pretest probability before testing.
Is this above the age adjusted threshold?
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Answer: D. It is positive: at age 58 the cutoff is 580 mcg/L, and 590 mcg/L warrants imaging.
Why: The correct FEU age-adjusted cutoff is age multiplied by 10 mcg/L, which is 580 at age 58. A result above the cutoff should be followed by imaging, not treated as diagnostic on its own. The tempting alternative, Use a fixed 500 mcg/L threshold and classify the result as negative because it is only 90 above normal, does not change the next step: at age 58 the age-adjusted threshold is 580 mcg/L, and 590 exceeds it; this result does not rule out PE.
- A. Choosing “Use a fixed 500 mcg/L threshold and classify the result as negative because it is only 90 above normal.” would lead to the wrong next step here because at age 58 the age-adjusted threshold is 580 mcg/L, and 590 exceeds it; this result does not rule out PE.
- B. Choosing “Set the age-adjusted cutoff at 710 mcg/L, the value used for a 71-year-old.” would lead to the wrong next step here because at age 58 the age-adjusted threshold is 580 mcg/L, and 590 exceeds it; this result does not rule out PE.
- C. Choosing “Diagnose PE from the positive D-dimer and begin anticoagulation without imaging.” would lead to the wrong next step here because at age 58 the age-adjusted threshold is 580 mcg/L, and 590 exceeds it; this result does not rule out PE.
Sources: Thrombosis Canada Clinical Guide, Pulmonary Embolism Diagnosis, version 30 April 2025
6 / 10
A 26-year-old with normal chest X-ray has positive D-dimer and needs imaging. The clinician records vital signs and estimates pretest probability before testing.
What option should be considered?
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Answer: B. Consider V/Q scanning: the patient is young and the chest radiograph is normal.
Why: A positive D-dimer indicates the need for imaging but does not dictate CTPA specifically. V/Q is a reasonable alternative in a young patient with a normal radiograph. The tempting alternative, Use a lower-extremity ultrasound as the definitive test even without leg symptoms, does not change the next step: in a young adult with a normal chest radiograph, V/Q can provide appropriate imaging while reducing breast radiation exposure.
- A. Choosing “Choose CTPA because a positive D-dimer makes V/Q scanning uninterpretable.” would lead to the wrong next step here because in a young adult with a normal chest radiograph, V/Q can provide appropriate imaging while reducing breast radiation exposure.
- C. Choosing “Repeat D-dimer after 48 hours and image only if it doubles.” would lead to the wrong next step here because in a young adult with a normal chest radiograph, V/Q can provide appropriate imaging while reducing breast radiation exposure.
- D. Choosing “Use a lower-extremity ultrasound as the definitive test even without leg symptoms.” would lead to the wrong next step here because in a young adult with a normal chest radiograph, V/Q can provide appropriate imaging while reducing breast radiation exposure.
Sources: Thrombosis Canada Clinical Guide, Pulmonary Embolism Diagnosis, version 30 April 2025
7 / 10
A 68-year-old with moderate probability has D-dimer 640 mcg/L. The clinician records vital signs and estimates pretest probability before testing.
Is this above the age adjusted threshold?
Show answer
Answer: A. No. At age 68, the age-adjusted cutoff is 680 mcg/L, so 640 mcg/L is negative.
Why: For patients aged 50 years or older, the FEU age-adjusted cutoff is age multiplied by 10 mcg/L in low or intermediate probability. A value below that threshold can exclude PE without imaging. The tempting alternative, Proceed to CTPA because age-adjusted D-dimer is not valid when probability is moderate, does not change the next step: at age 68, age multiplied by 10 gives a cutoff of 680 mcg/L; 640 is below it.
- B. Choosing “Use the fixed 500 mcg/L cutoff and classify 640 as positive.” would lead to the wrong next step here because at age 68, age multiplied by 10 gives a cutoff of 680 mcg/L; 640 is below it.
- C. Choosing “Use 6800 mcg/L because the age-adjusted formula multiplies age by 100.” would lead to the wrong next step here because at age 68, age multiplied by 10 gives a cutoff of 680 mcg/L; 640 is below it.
- D. Choosing “Proceed to CTPA because age-adjusted D-dimer is not valid when probability is moderate.” would lead to the wrong next step here because at age 68, age multiplied by 10 gives a cutoff of 680 mcg/L; 640 is below it.
Sources: Thrombosis Canada Clinical Guide, Pulmonary Embolism Diagnosis, version 30 April 2025
8 / 10
A 58-year-old has a D-dimer of 570 mcg/L and low probability. The clinician records vital signs and estimates pretest probability before testing.
What threshold applies?
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Answer: C. The age-adjusted cutoff is 580 mcg/L; 570 mcg/L is negative in this low-probability patient.
Why: Age-adjusted D-dimer can exclude PE in low or intermediate probability when the result is below age multiplied by 10 mcg/L. A positive result would prompt imaging, not establish PE by itself. The tempting alternative, Treat 570 mcg/L as diagnostic of PE and start anticoagulation without imaging, does not change the next step: at age 58, the FEU age-adjusted cutoff is 58 times 10, or 580 mcg/L; 570 is below it.
- A. Choosing “Use 500 mcg/L for all ages and classify 570 mcg/L as positive.” would lead to the wrong next step here because at age 58, the FEU age-adjusted cutoff is 58 times 10, or 580 mcg/L; 570 is below it.
- B. Choosing “Use 5800 mcg/L because the age-adjustment formula multiplies by 100.” would lead to the wrong next step here because at age 58, the FEU age-adjusted cutoff is 58 times 10, or 580 mcg/L; 570 is below it.
- D. Choosing “Treat 570 mcg/L as diagnostic of PE and start anticoagulation without imaging.” would lead to the wrong next step here because at age 58, the FEU age-adjusted cutoff is 58 times 10, or 580 mcg/L; 570 is below it.
Sources: Thrombosis Canada Clinical Guide, Pulmonary Embolism Diagnosis, version 30 April 2025
9 / 10
A 63-year-old has a D-dimer of 650 mcg/L and low probability. The clinician records vital signs and estimates pretest probability before testing.
How does the age adjusted threshold classify it?
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Answer: D. The cutoff is 630 mcg/L at age 63; 650 mcg/L is positive, so proceed to imaging.
Why: The age-adjusted FEU threshold is age multiplied by 10 mcg/L, yielding 630 at age 63. The positive result does not diagnose PE, so imaging is the next step. The tempting alternative, Use 1000 mcg/L for all patients with no hemoptysis and classify 650 as negative without applying YEARS, does not change the next step: at age 63, age multiplied by 10 gives 630 mcg/L; 650 exceeds the cutoff and requires imaging to evaluate PE.
- A. Choosing “Use 580 mcg/L, the cutoff for age 58, and classify 650 as positive.” would lead to the wrong next step here because at age 63, age multiplied by 10 gives 630 mcg/L; 650 exceeds the cutoff and requires imaging to evaluate PE.
- B. Choosing “Use 1000 mcg/L for all patients with no hemoptysis and classify 650 as negative without applying YEARS.” would lead to the wrong next step here because at age 63, age multiplied by 10 gives 630 mcg/L; 650 exceeds the cutoff and requires imaging to evaluate PE.
- C. Choosing “Diagnose PE and begin anticoagulation because 650 mcg/L is above the age-adjusted cutoff.” would lead to the wrong next step here because at age 63, age multiplied by 10 gives 630 mcg/L; 650 exceeds the cutoff and requires imaging to evaluate PE.
Sources: Thrombosis Canada Clinical Guide, Pulmonary Embolism Diagnosis, version 30 April 2025
10 / 10
A 68-year-old has a sensitive D-dimer of 700 mcg/L and low probability. The clinician records vital signs and estimates pretest probability before testing.
Is the result positive using the age adjusted threshold?
Show answer
Answer: B. Yes. At age 68, 700 mcg/L exceeds the age-adjusted cutoff of 680 mcg/L; obtain imaging.
Why: The age-adjusted FEU threshold is age multiplied by 10 mcg/L from age 50 onward. A result above the cutoff is positive for the diagnostic pathway and should lead to imaging in this low-probability patient. The tempting alternative, Use the fixed 500 mcg/L cutoff and call this negative because the value is close to normal, does not change the next step: age 68 gives an age-adjusted cutoff of 680 mcg/L, and 700 is above it, so PE is not excluded.
- A. Choosing “Use the fixed 500 mcg/L cutoff and call this negative because the value is close to normal.” would lead to the wrong next step here because age 68 gives an age-adjusted cutoff of 680 mcg/L, and 700 is above it, so PE is not excluded.
- C. Choosing “Raise the threshold to 1000 mcg/L because the patient is older than 50.” would lead to the wrong next step here because age 68 gives an age-adjusted cutoff of 680 mcg/L, and 700 is above it, so PE is not excluded.
- D. Choosing “Repeat the assay using a less sensitive method before deciding whether to image.” would lead to the wrong next step here because age 68 gives an age-adjusted cutoff of 680 mcg/L, and 700 is above it, so PE is not excluded.
Sources: Thrombosis Canada Clinical Guide, Pulmonary Embolism Diagnosis, version 30 April 2025
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Exam-style questions written by MedHub for practice. They are not official exam questions.