NSG 550 Exam 3 Diagnostic Reasoning
(2026/2027) PDF | Nursing | Wilkes University
1. A nurse practitioner uses a 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 vs. 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.
Answer: B
Rationale: Type 1 (intuitive) reasoning is rapid,
subconscious, and pattern-based. Recognizing illness
severity instantly is a hallmark of intuitive processing.
1
,Options A, C, and D involve deliberate, analytical (Type
2) reasoning.
2. A 45-year-old presents with epigastric pain. You
generate 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
Answer: C
Rationale: An exhaustive differential includes all
reasonable possibilities before narrowing. The working
diagnosis is the most likely after reasoning. Anatomical
differential organizes by organ system.
3. The “sensitivity” of a diagnostic test refers to its ability
to:
A) Correctly identify those without the disease (true
2
,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
Answer: B
Rationale: Sensitivity = TP/(TP+FN). High sensitivity rules
out disease when negative (SnNout). Specificity (option A)
rules in disease when positive (SpPin).
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
Answer: B
Rationale: PPV varies directly with prevalence. In low
3
, prevalence, even a highly specific test yields many false
positives → low PPV. Likelihood ratios are less affected
by prevalence.
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
Answer: B
Rationale: Availability heuristic—recent or memorable
cases overestimate likelihood. Anchoring is fixating on
initial data. Confirmation bias seeks supporting evidence.
Premature closure stops too early.
6. To avoid premature closure, an NP should:
A) Stop ordering tests once the most likely diagnosis is
found
4
(2026/2027) PDF | Nursing | Wilkes University
1. A nurse practitioner uses a 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 vs. 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.
Answer: B
Rationale: Type 1 (intuitive) reasoning is rapid,
subconscious, and pattern-based. Recognizing illness
severity instantly is a hallmark of intuitive processing.
1
,Options A, C, and D involve deliberate, analytical (Type
2) reasoning.
2. A 45-year-old presents with epigastric pain. You
generate 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
Answer: C
Rationale: An exhaustive differential includes all
reasonable possibilities before narrowing. The working
diagnosis is the most likely after reasoning. Anatomical
differential organizes by organ system.
3. The “sensitivity” of a diagnostic test refers to its ability
to:
A) Correctly identify those without the disease (true
2
,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
Answer: B
Rationale: Sensitivity = TP/(TP+FN). High sensitivity rules
out disease when negative (SnNout). Specificity (option A)
rules in disease when positive (SpPin).
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
Answer: B
Rationale: PPV varies directly with prevalence. In low
3
, prevalence, even a highly specific test yields many false
positives → low PPV. Likelihood ratios are less affected
by prevalence.
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
Answer: B
Rationale: Availability heuristic—recent or memorable
cases overestimate likelihood. Anchoring is fixating on
initial data. Confirmation bias seeks supporting evidence.
Premature closure stops too early.
6. To avoid premature closure, an NP should:
A) Stop ordering tests once the most likely diagnosis is
found
4
