,NSG550/NSG 550 Exam 3 Diagnostic Reasoning for
1. A nurse practitioner uses the dual-process model of reasoning. Which scenario best describes the
intuitive (Type 1) process?
A) Calculating pre-test probability for pulmonary embolism using the Wells score
B) Recognizing "sick versus not sick" within seconds of entering a patient's room
C) Listing all possible causes of fatigue and ruling each out systematically
D) Using a clinical decision rule to decide on imaging for ankle trauma
Correct Answer: Recognizing "sick versus not sick" within seconds of entering a patient's room
Rationale: Type 1 (intuitive) reasoning is rapid, subconscious, and pattern-based, often described as
"gut feeling." Recognizing illness severity instantly is a hallmark of this process. Options A, C, and D
involve deliberate, analytical (Type 2) reasoning that is slower and more effortful.
2. A 45-year-old presents with epigastric pain. The NP generates a differential that includes GERD,
peptic ulcer disease, biliary colic, and cardiac ischemia. This list represents the:
A) Working diagnosis
B) Anatomical differential
C) Exhaustive differential
D) Pathophysiologic cascade
Correct Answer: Exhaustive differential
Rationale: An exhaustive differential includes all reasonable possibilities before narrowing the list
based on clinical data. The working diagnosis is the most likely after reasoning. An anatomical
differential organizes possibilities by organ system. A pathophysiologic cascade traces the mechanism
of disease.
3. The "sensitivity" of a diagnostic test refers to its ability to:
A) Correctly identify those without the disease (true negative rate)
B) Correctly identify those with the disease (true positive rate)
C) Produce the same result on repeated testing
D) Predict the probability of disease after a positive result
Correct Answer: Correctly identify those with the disease (true positive rate)
,Rationale: Sensitivity is the proportion of people with the disease who test positive, calculated as
TP/(TP+FN). High sensitivity rules out disease when negative (SnNOUT). Specificity (option A) rules in
disease when positive (SpPIN). Reliability is reproducibility, and predictive value reflects post-test
probability.
4. A test with 95% specificity is used in a low-prevalence population. A positive result most likely
indicates:
A) High positive predictive value
B) Low positive predictive value
C) Low negative predictive value
D) High likelihood ratio for disease
Correct Answer: Low positive predictive value
Rationale: Positive predictive value varies directly with disease prevalence. In low-prevalence
populations, even a highly specific test yields many false positives, resulting in low PPV. Likelihood
ratios are less affected by prevalence and better reflect test performance.
5. Which heuristic is defined as "the tendency to judge the probability of an event by how easily
examples come to mind"?
A) Anchoring
B) Availability
C) Confirmation bias
D) Premature closure
Correct Answer: Availability
Rationale: The availability heuristic leads clinicians to overestimate the likelihood of diagnoses that
are recent, memorable, or emotionally charged. Anchoring is fixating on initial data. Confirmation bias
seeks supporting evidence. Premature closure stops the diagnostic process too early.
6. To avoid premature closure, an NP should:
A) Stop ordering tests once the most likely diagnosis is found
B) Generate a differential diagnosis and revisit it as new data emerge
C) Rely exclusively on the first hypothesis
D) Avoid considering uncommon diagnoses
, Correct Answer: Generate a differential diagnosis and revisit it as new data emerge
Rationale: Premature closure occurs when a clinician stops considering alternatives after reaching a
preliminary conclusion. Maintaining an open mind, generating a broad differential, and revisiting it as
new data emerge are essential strategies to avoid this cognitive error.
7. A 62-year-old male presents with crushing substernal chest pain radiating to the left arm,
accompanied by diaphoresis and nausea. Which test should be performed first?
A) Chest X-ray
B) Electrocardiogram
C) Cardiac troponin
D) Echocardiogram
Correct Answer: Electrocardiogram
Rationale: ECG is the first and most essential test for evaluating suspected myocardial infarction, as it
is rapid, widely available, and can identify ST-segment elevation requiring immediate intervention.
Troponin is diagnostic but takes time to rise. Chest X-ray and echocardiogram are not first-line for
acute chest pain.
8. A 55-year-old male with sudden onset of severe, tearing chest pain radiating to the back. Which
diagnosis must be urgently considered?
A) Acute myocardial infarction
B) Pulmonary embolism
C) Aortic dissection
D) Pericarditis
Correct Answer: Aortic dissection
Rationale: Acute aortic dissection classically presents with sudden, severe, tearing chest or back pain
that may migrate. This is a surgical emergency requiring immediate imaging (CT angiography). MI
presents with pressure-like pain, PE with pleuritic pain and dyspnea, and pericarditis with positional
pain improved by leaning forward.
9. A patient with suspected heart failure has an elevated B-type natriuretic peptide (BNP). What does
this suggest?
A) Likely heart failure
B) Renal dysfunction
1. A nurse practitioner uses the dual-process model of reasoning. Which scenario best describes the
intuitive (Type 1) process?
A) Calculating pre-test probability for pulmonary embolism using the Wells score
B) Recognizing "sick versus not sick" within seconds of entering a patient's room
C) Listing all possible causes of fatigue and ruling each out systematically
D) Using a clinical decision rule to decide on imaging for ankle trauma
Correct Answer: Recognizing "sick versus not sick" within seconds of entering a patient's room
Rationale: Type 1 (intuitive) reasoning is rapid, subconscious, and pattern-based, often described as
"gut feeling." Recognizing illness severity instantly is a hallmark of this process. Options A, C, and D
involve deliberate, analytical (Type 2) reasoning that is slower and more effortful.
2. A 45-year-old presents with epigastric pain. The NP generates a differential that includes GERD,
peptic ulcer disease, biliary colic, and cardiac ischemia. This list represents the:
A) Working diagnosis
B) Anatomical differential
C) Exhaustive differential
D) Pathophysiologic cascade
Correct Answer: Exhaustive differential
Rationale: An exhaustive differential includes all reasonable possibilities before narrowing the list
based on clinical data. The working diagnosis is the most likely after reasoning. An anatomical
differential organizes possibilities by organ system. A pathophysiologic cascade traces the mechanism
of disease.
3. The "sensitivity" of a diagnostic test refers to its ability to:
A) Correctly identify those without the disease (true negative rate)
B) Correctly identify those with the disease (true positive rate)
C) Produce the same result on repeated testing
D) Predict the probability of disease after a positive result
Correct Answer: Correctly identify those with the disease (true positive rate)
,Rationale: Sensitivity is the proportion of people with the disease who test positive, calculated as
TP/(TP+FN). High sensitivity rules out disease when negative (SnNOUT). Specificity (option A) rules in
disease when positive (SpPIN). Reliability is reproducibility, and predictive value reflects post-test
probability.
4. A test with 95% specificity is used in a low-prevalence population. A positive result most likely
indicates:
A) High positive predictive value
B) Low positive predictive value
C) Low negative predictive value
D) High likelihood ratio for disease
Correct Answer: Low positive predictive value
Rationale: Positive predictive value varies directly with disease prevalence. In low-prevalence
populations, even a highly specific test yields many false positives, resulting in low PPV. Likelihood
ratios are less affected by prevalence and better reflect test performance.
5. Which heuristic is defined as "the tendency to judge the probability of an event by how easily
examples come to mind"?
A) Anchoring
B) Availability
C) Confirmation bias
D) Premature closure
Correct Answer: Availability
Rationale: The availability heuristic leads clinicians to overestimate the likelihood of diagnoses that
are recent, memorable, or emotionally charged. Anchoring is fixating on initial data. Confirmation bias
seeks supporting evidence. Premature closure stops the diagnostic process too early.
6. To avoid premature closure, an NP should:
A) Stop ordering tests once the most likely diagnosis is found
B) Generate a differential diagnosis and revisit it as new data emerge
C) Rely exclusively on the first hypothesis
D) Avoid considering uncommon diagnoses
, Correct Answer: Generate a differential diagnosis and revisit it as new data emerge
Rationale: Premature closure occurs when a clinician stops considering alternatives after reaching a
preliminary conclusion. Maintaining an open mind, generating a broad differential, and revisiting it as
new data emerge are essential strategies to avoid this cognitive error.
7. A 62-year-old male presents with crushing substernal chest pain radiating to the left arm,
accompanied by diaphoresis and nausea. Which test should be performed first?
A) Chest X-ray
B) Electrocardiogram
C) Cardiac troponin
D) Echocardiogram
Correct Answer: Electrocardiogram
Rationale: ECG is the first and most essential test for evaluating suspected myocardial infarction, as it
is rapid, widely available, and can identify ST-segment elevation requiring immediate intervention.
Troponin is diagnostic but takes time to rise. Chest X-ray and echocardiogram are not first-line for
acute chest pain.
8. A 55-year-old male with sudden onset of severe, tearing chest pain radiating to the back. Which
diagnosis must be urgently considered?
A) Acute myocardial infarction
B) Pulmonary embolism
C) Aortic dissection
D) Pericarditis
Correct Answer: Aortic dissection
Rationale: Acute aortic dissection classically presents with sudden, severe, tearing chest or back pain
that may migrate. This is a surgical emergency requiring immediate imaging (CT angiography). MI
presents with pressure-like pain, PE with pleuritic pain and dyspnea, and pericarditis with positional
pain improved by leaning forward.
9. A patient with suspected heart failure has an elevated B-type natriuretic peptide (BNP). What does
this suggest?
A) Likely heart failure
B) Renal dysfunction
