NR 569 MIDTERM EXAM 2026/2027 | Differential
Diagnosis in Acute Care Practicum Review
Section 1: Foundations of Diagnostic Reasoning (Q1–15)
Q1. A 68-year-old male presents to the ED with acute onset chest pain. The ACNP begins
generating diagnostic hypotheses. Which approach best reflects the hypothesis-driven
method of diagnostic reasoning?
A. Order a comprehensive metabolic panel and wait for results before forming any clinical
impression
B. Generate multiple competing diagnoses simultaneously based on the initial presentation,
then systematically rule them in or out
C. Rely solely on pattern recognition from previous similar patients to arrive at a single diagnosis
immediately
D. Refer the patient to a specialist before initiating any diagnostic workup given the complexity
Answer: B
Rationale: The hypothesis-driven method involves generating multiple diagnostic hypotheses
early based on initial data, then systematically testing each through focused assessment. This
reduces cognitive bias and anchoring, which are leading causes of diagnostic error in acute care
.
Q2. An ACNP evaluates a 55-year-old female with dyspnea. The Wells score estimates PE pre-
test probability at 15%. A D-dimer returns at 450 ng/mL (negative below 500). Using Bayesian
analysis, what is the most appropriate next step?
A. Discharge the patient since the negative D-dimer conclusively rules out PE
B. Proceed directly to CTPA because the pre-test probability is too high for D-dimer
C. Calculate post-test probability using the negative likelihood ratio to determine if PE is
excluded
D. Repeat the D-dimer in 24 hours to confirm the negative result before disposition
Answer: C
Rationale: Bayesian analysis requires combining pre-test probability with test characteristics
(likelihood ratios) to determine post-test probability. A D-dimer near the cutoff with moderate
pre-test probability does not automatically exclude PE; the negative likelihood ratio must be
applied .
Q3. A 42-year-old female has 2 weeks of progressive fatigue, myalgias, and low-grade fevers.
She now presents with new petechiae on her lower extremities and gum bleeding. Which red
,flag most significantly changes diagnostic urgency?
A. Duration of symptoms extending beyond 10 days without improvement
B. New onset bleeding manifestations suggesting a potential hematologic emergency
C. Presence of myalgias which could indicate an autoimmune process
D. Low-grade fevers suggesting an undiagnosed infectious etiology requiring antibiotics
Answer: B
Rationale: New bleeding manifestations with progressive constitutional symptoms is a critical
red flag suggesting thrombocytopenia with bleeding risk, potentially indicating acute leukemia,
aplastic anemia, DIC, or severe sepsis. Immediate CBC with differential, coagulation studies, and
peripheral smear are required .
Q4. In the NGN Clinical Judgment Measurement Model (CJMM), which action best represents
the “Analyze Cues” step when a 75-year-old presents with confusion, hypotension (BP 88/50),
and temperature 38.9°C?
A. Immediately administer broad-spectrum antibiotics and isotonic IV fluids
B. Recognize that the combination of altered mental status, hemodynamic instability, and fever
form a cluster suggesting sepsis
C. Prioritize which diagnosis is most likely before obtaining additional clinical data
D. Evaluate the patient response to initial fluid resuscitation after 30 minutes
Answer: B
Rationale: The Analyze Cues step in the CJMM involves recognizing patterns and relationships
among clinical data. The combination of altered mental status, hypotension, and fever forms a
sepsis cluster .
Q5. A diagnostic test has a sensitivity of 98% for detecting pulmonary embolism. Using the
SnNout principle, how should a negative result be interpreted?
A. The negative result rules in the diagnosis of PE
B. The negative result effectively rules out the diagnosis of PE
C. The negative result is inconclusive
D. The negative result has no diagnostic value
Answer: B
Rationale: SnNout: when a test has high Snsitivity, a Negative result rules out the disease. A
sensitivity of 98% means a negative result effectively rules out PE .
Q6. A test for PE has a specificity of 95%. Using the SpPin principle, how should a positive
result be interpreted?
A. The positive result rules out the disease
B. The positive result rules in the disease
, C. The positive result is inconclusive
D. The positive result has no diagnostic value
Answer: B
Rationale: SPin: when a test has high Specificity, a Positive result rules in the disease. Specificity
refers to the ability of a test to recognize patients who do not have the disease .
Q7. A test for PE has a positive predictive value (PPV) of 65% in a patient with low pre-test
probability (10%). What does this mean?
A. The test is highly accurate and confirms PE
B. 35% of positive results will be false positives
C. The test should not be used for PE diagnosis
D. The negative predictive value is also low
Answer: B
Rationale: PPV is the probability that a patient has the disease after testing positive. PPV is
markedly dependent on disease prevalence. With low pre-test probability, even a specific test
yields a low PPV, meaning many positive results are false positives .
Q8. Which of the following best describes the sensitivity formula?
A. TN / (TN + FP)
B. TP / (TP + FN)
C. TP / (TP + FP)
D. TN / (TN + FN)
Answer: B
Rationale: Sensitivity = TP / (TP + FN). The number of patients who have the disease and test
positive is divided by all who have the disease, including those who falsely test negative .
Q9. Which of the following best describes the specificity formula?
A. TN / (TN + FP)
B. TP / (TP + FN)
C. TP / (TP + FP)
D. TN / (TN + FN)
Answer: A
Rationale: Specificity = TN / (TN + FP). The number of patients who test negative and do not
have the disease is divided by the total number without the disease .
Q10. A clinician uses pattern recognition to rapidly diagnose a classic presentation of
appendicitis. Which cognitive process is being utilized?
A. Analytical reasoning
Diagnosis in Acute Care Practicum Review
Section 1: Foundations of Diagnostic Reasoning (Q1–15)
Q1. A 68-year-old male presents to the ED with acute onset chest pain. The ACNP begins
generating diagnostic hypotheses. Which approach best reflects the hypothesis-driven
method of diagnostic reasoning?
A. Order a comprehensive metabolic panel and wait for results before forming any clinical
impression
B. Generate multiple competing diagnoses simultaneously based on the initial presentation,
then systematically rule them in or out
C. Rely solely on pattern recognition from previous similar patients to arrive at a single diagnosis
immediately
D. Refer the patient to a specialist before initiating any diagnostic workup given the complexity
Answer: B
Rationale: The hypothesis-driven method involves generating multiple diagnostic hypotheses
early based on initial data, then systematically testing each through focused assessment. This
reduces cognitive bias and anchoring, which are leading causes of diagnostic error in acute care
.
Q2. An ACNP evaluates a 55-year-old female with dyspnea. The Wells score estimates PE pre-
test probability at 15%. A D-dimer returns at 450 ng/mL (negative below 500). Using Bayesian
analysis, what is the most appropriate next step?
A. Discharge the patient since the negative D-dimer conclusively rules out PE
B. Proceed directly to CTPA because the pre-test probability is too high for D-dimer
C. Calculate post-test probability using the negative likelihood ratio to determine if PE is
excluded
D. Repeat the D-dimer in 24 hours to confirm the negative result before disposition
Answer: C
Rationale: Bayesian analysis requires combining pre-test probability with test characteristics
(likelihood ratios) to determine post-test probability. A D-dimer near the cutoff with moderate
pre-test probability does not automatically exclude PE; the negative likelihood ratio must be
applied .
Q3. A 42-year-old female has 2 weeks of progressive fatigue, myalgias, and low-grade fevers.
She now presents with new petechiae on her lower extremities and gum bleeding. Which red
,flag most significantly changes diagnostic urgency?
A. Duration of symptoms extending beyond 10 days without improvement
B. New onset bleeding manifestations suggesting a potential hematologic emergency
C. Presence of myalgias which could indicate an autoimmune process
D. Low-grade fevers suggesting an undiagnosed infectious etiology requiring antibiotics
Answer: B
Rationale: New bleeding manifestations with progressive constitutional symptoms is a critical
red flag suggesting thrombocytopenia with bleeding risk, potentially indicating acute leukemia,
aplastic anemia, DIC, or severe sepsis. Immediate CBC with differential, coagulation studies, and
peripheral smear are required .
Q4. In the NGN Clinical Judgment Measurement Model (CJMM), which action best represents
the “Analyze Cues” step when a 75-year-old presents with confusion, hypotension (BP 88/50),
and temperature 38.9°C?
A. Immediately administer broad-spectrum antibiotics and isotonic IV fluids
B. Recognize that the combination of altered mental status, hemodynamic instability, and fever
form a cluster suggesting sepsis
C. Prioritize which diagnosis is most likely before obtaining additional clinical data
D. Evaluate the patient response to initial fluid resuscitation after 30 minutes
Answer: B
Rationale: The Analyze Cues step in the CJMM involves recognizing patterns and relationships
among clinical data. The combination of altered mental status, hypotension, and fever forms a
sepsis cluster .
Q5. A diagnostic test has a sensitivity of 98% for detecting pulmonary embolism. Using the
SnNout principle, how should a negative result be interpreted?
A. The negative result rules in the diagnosis of PE
B. The negative result effectively rules out the diagnosis of PE
C. The negative result is inconclusive
D. The negative result has no diagnostic value
Answer: B
Rationale: SnNout: when a test has high Snsitivity, a Negative result rules out the disease. A
sensitivity of 98% means a negative result effectively rules out PE .
Q6. A test for PE has a specificity of 95%. Using the SpPin principle, how should a positive
result be interpreted?
A. The positive result rules out the disease
B. The positive result rules in the disease
, C. The positive result is inconclusive
D. The positive result has no diagnostic value
Answer: B
Rationale: SPin: when a test has high Specificity, a Positive result rules in the disease. Specificity
refers to the ability of a test to recognize patients who do not have the disease .
Q7. A test for PE has a positive predictive value (PPV) of 65% in a patient with low pre-test
probability (10%). What does this mean?
A. The test is highly accurate and confirms PE
B. 35% of positive results will be false positives
C. The test should not be used for PE diagnosis
D. The negative predictive value is also low
Answer: B
Rationale: PPV is the probability that a patient has the disease after testing positive. PPV is
markedly dependent on disease prevalence. With low pre-test probability, even a specific test
yields a low PPV, meaning many positive results are false positives .
Q8. Which of the following best describes the sensitivity formula?
A. TN / (TN + FP)
B. TP / (TP + FN)
C. TP / (TP + FP)
D. TN / (TN + FN)
Answer: B
Rationale: Sensitivity = TP / (TP + FN). The number of patients who have the disease and test
positive is divided by all who have the disease, including those who falsely test negative .
Q9. Which of the following best describes the specificity formula?
A. TN / (TN + FP)
B. TP / (TP + FN)
C. TP / (TP + FP)
D. TN / (TN + FN)
Answer: A
Rationale: Specificity = TN / (TN + FP). The number of patients who test negative and do not
have the disease is divided by the total number without the disease .
Q10. A clinician uses pattern recognition to rapidly diagnose a classic presentation of
appendicitis. Which cognitive process is being utilized?
A. Analytical reasoning
