NR569 / NR 569 Midterm Exam
Differential Diagnosis in Acute Care Practicum
Latest Update | Questions and Verified Answers | 100% Correct | Grade A
Chamberlain University College of Nursing
Section 1: Clinical Reasoning and Diagnostic Frameworks (Q1 - Q15)
Q1. An acute care NP presents a patient with acute dyspnea to the preceptor using the SNAPPS framework. The NP
summarizes the history, narrows the differential to pneumonia versus PE, analyzes pertinent positives and negatives,
then asks the preceptor about the limitations of D-dimer testing. Which component of SNAPPS does this step
represent?
A. Summarize
B. Narrow
C. Analyze
D. Probe **[CORRECT]**
Correct Answer: D | Rationale: Probe involves the learner asking questions about clinical reasoning, diagnostic uncertainties, and
management alternatives, identifying knowledge gaps. Summarize restates the case, Narrow reduces the differential, and Analyze
compares diagnoses.
Q2. A patient presents with acute substernal chest pain. Using OLDCARTS, the NP documents pain began 2 hours
ago while climbing stairs, located retrosternally radiating to left arm, constant pressure-like, worsened by exertion
and relieved by rest, occurs with activity, rated 8/10. Which OLDCARTS components are most critical for
differentiating ACS from other chest pain causes?
A. Onset and Location
B. Aggravating/Relieving factors and Timing **[CORRECT]**
C. Character and Severity
D. Duration and Radiation
Correct Answer: B | Rationale: Aggravating/Relieving factors and Timing are most critical because pain provoked by exertion
and relieved by rest, with relationship to activity, are hallmark features of cardiac ischemia distinguishing it from GERD,
musculoskeletal pain, or anxiety.
Q3. A diagnostic test for PE has 95% sensitivity and 40% specificity. The NP orders D-dimer for a low pre-test
probability patient. The result is negative. Which principle guides interpretation?
A. SpPin: specific positive rules in disease
B. SnNout: sensitive negative rules out disease **[CORRECT]**
C. Negative result unreliable due to low specificity
D. Test should be repeated because specificity below 50%
Correct Answer: B | Rationale: SnNout states that a test with high sensitivity, when negative, rules out disease. D-dimer with 95%
sensitivity means a negative result effectively excludes PE in low pre-test probability patients, the basis for the Wells/D-dimer PE
algorithm.
Q4. A 62-year-old presents with worst headache of life. Pre-test probability of SAH is 5%. Non-contrast head CT is
negative (98% sensitivity within 6 hours). What is the approximate post-test probability?
A. Less than 0.1% **[CORRECT]**
B. Approximately 1%
C. Approximately 5%
Page 1
, D. Approximately 10%
Correct Answer: A | Rationale: Using Bayesian reasoning, a pre-test probability of 5% with a highly sensitive negative CT (LR-
approximately 0.02) yields a post-test probability below 0.1%. However, lumbar puncture is still recommended because
consequences of missed SAH are catastrophic, showing that clinical reasoning integrates both probability and consequence.
Q5. A patient has Wells DVT score of 1 (moderate probability) and negative D-dimer. The NP concludes DVT is
ruled out without further testing. Which principle supports this?
A. Negative highly sensitive test in low-to-moderate pre-test probability excludes DVT
**[CORRECT]**
B. D-dimer has high specificity confirming absence of DVT
C. Wells score 1 indicates high probability so D-dimer should not be ordered
D. Negative D-dimer eliminates need for clinical assessment
Correct Answer: A | Rationale: D-dimer is highly sensitive, so a negative result in low-to-moderate pre-test probability (Wells 0-2)
effectively rules out DVT. For high probability (Wells 3+), D-dimer is less useful and duplex ultrasound should be obtained
directly.
Q6. Which best describes the purpose of SNAPPS in acute care NP education?
A. To replace comprehensive health history
B. To provide a learner-centered framework for case presentation promoting clinical reasoning and
differential diagnosis development **[CORRECT]**
C. To standardize EHR documentation
D. To prioritize life-threatening conditions
Correct Answer: B | Rationale: SNAPPS is a six-step learner-centered framework (Summarize, Narrow, Analyze, Probe, Plan,
Select) designed to enhance clinical reasoning during case presentations, engaging learners in differential diagnosis construction
and self-assessment of knowledge gaps.
Q7. A 45-year-old with acute abdominal pain has 30% pre-test probability of appendicitis and Alvarado score of 5.
CT with IV contrast (94% sensitivity, 95% specificity) is positive. What happens to post-test probability?
A. Decreases because Alvarado was only 5
B. Increases substantially because positive result on high-specificity test in moderate pre-test
probability raises disease likelihood **[CORRECT]**
C. Remains unchanged at 30%
D. Cannot be calculated without population prevalence
Correct Answer: B | Rationale: SpPin states a test with high specificity, when positive, rules in disease. CT with 95% specificity
(LR+ = 18.8) and a positive result in a patient with 30% pre-test probability raises post-test probability to approximately 88-90%,
demonstrating how specific tests dramatically increase diagnostic probability.
Q8. An NP conducts a focused interview with a patient with acute chest pain. The NP maintains eye contact, nods,
reflects the patients emotional state, and uses silence to allow the patient to elaborate. Which component of skilled
interviewing is being demonstrated?
A. Directive questioning
B. Active or attentive listening and connecting to the patients emotional state **[CORRECT]**
C. Biomedical data collection
D. Rapid hypothesis generation
Correct Answer: B | Rationale: Active or attentive listening involves verbal and nonverbal techniques (eye contact, nodding,
reflection, therapeutic silence) that encourage patient expression and demonstrate empathy. This is a core component of skilled
interviewing in the SNAPPS framework, essential for building rapport and obtaining accurate subjective data.
Q9. A new biomarker for sepsis has a sensitivity of 85% and specificity of 80% in an ICU population with 40%
sepsis prevalence. What is the expected positive predictive value (PPV) compared to the same test applied to an ED
population with 10% prevalence?
, A. PPV will be higher in the ED population
B. PPV will be lower in the ED population **[CORRECT]**
C. PPV will be identical in both populations
D. PPV depends only on sensitivity and specificity, not prevalence
Correct Answer: B | Rationale: PPV is directly influenced by disease prevalence; it increases as prevalence increases and
decreases as prevalence decreases. In the ICU (40% prevalence), PPV will be substantially higher than in the ED (10%
prevalence), even though the test characteristics are identical. This is why the same test can be more useful in a referral population
than in a screening population.
Q10. A diagnostic test for acute appendicitis has a positive likelihood ratio (LR+) of 12. The pre-test probability of
appendicitis is 25%. After a positive test result, the post-test probability is approximately 80%. What does the LR+ of
12 indicate?
A. The test is 12 times more likely to be negative in patients with appendicitis
B. A positive result is 12 times more likely in a patient with appendicitis than without it
**[CORRECT]**
C. The test has a 12% false positive rate
D. The test correctly identifies 88% of patients with appendicitis
Correct Answer: B | Rationale: LR+ equals sensitivity divided by (1 minus specificity). An LR+ of 12 means a positive test result
is 12 times more likely in a patient who has the disease compared to one without it. LR+ greater than 10 is considered strong
evidence for ruling in a diagnosis. This is distinct from sensitivity, specificity, and PPV, though it relates to all three.
Q11. A 55-year-old presents with acute dyspnea and pleuritic chest pain. The NP notes tachycardia (HR 112),
hypoxia (SpO2 88%), and unilateral left leg swelling. The NP also notes absence of fever and normal breath sounds.
Which findings are pertinent positives and pertinent negatives for pulmonary embolism, respectively?
A. Tachycardia and hypoxia are pertinent positives; fever absence and normal breath sounds are
pertinent negatives **[CORRECT]**
B. Pleuritic chest pain and tachycardia are pertinent positives; SpO2 of 88% is a pertinent negative
C. Unilateral leg swelling is the only pertinent positive; all others are pertinent negatives
D. There are no pertinent negatives in this presentation
Correct Answer: A | Rationale: Pertinent positives are findings that support a specific diagnosis (tachycardia, hypoxia, pleuritic
chest pain, and leg swelling support PE). Pertinent negatives are expected findings that are absent, helping to rule out alternative
diagnoses (absence of fever and normal breath sounds make pneumonia less likely). Distinguishing these is fundamental to
differential diagnosis construction in acute care.
Q12. A negative likelihood ratio (LR-) of 0.1 for a diagnostic test of heart failure using NT-proBNP is reported.
What does this value indicate?
A. A negative test result reduces the odds of heart failure by 90%
B. A negative result is only 10% as likely in a patient with heart failure compared to one without
**[CORRECT]**
C. The test has 90% specificity
D. The false negative rate is 10%
Correct Answer: B | Rationale: LR- equals (1 minus sensitivity) divided by specificity. An LR- of 0.1 means a negative result is
only one-tenth as likely in a patient with the disease compared to one without the disease. An LR- less than 0.1 is considered strong
evidence for ruling out a diagnosis (SnNout equivalent). This is particularly useful for NT-proBNP, where very low values
effectively exclude heart failure.
Q13. A patient presents with acute dyspnea, tachycardia, and hypoxia. The NP constructs a differential including PE,
pneumonia, COPD exacerbation, pneumothorax, and heart failure. Which approach best describes this process?
A. Pattern recognition only
B. Hypothesis generation creating a comprehensive differential that can be systematically tested and
refined **[CORRECT]**
Differential Diagnosis in Acute Care Practicum
Latest Update | Questions and Verified Answers | 100% Correct | Grade A
Chamberlain University College of Nursing
Section 1: Clinical Reasoning and Diagnostic Frameworks (Q1 - Q15)
Q1. An acute care NP presents a patient with acute dyspnea to the preceptor using the SNAPPS framework. The NP
summarizes the history, narrows the differential to pneumonia versus PE, analyzes pertinent positives and negatives,
then asks the preceptor about the limitations of D-dimer testing. Which component of SNAPPS does this step
represent?
A. Summarize
B. Narrow
C. Analyze
D. Probe **[CORRECT]**
Correct Answer: D | Rationale: Probe involves the learner asking questions about clinical reasoning, diagnostic uncertainties, and
management alternatives, identifying knowledge gaps. Summarize restates the case, Narrow reduces the differential, and Analyze
compares diagnoses.
Q2. A patient presents with acute substernal chest pain. Using OLDCARTS, the NP documents pain began 2 hours
ago while climbing stairs, located retrosternally radiating to left arm, constant pressure-like, worsened by exertion
and relieved by rest, occurs with activity, rated 8/10. Which OLDCARTS components are most critical for
differentiating ACS from other chest pain causes?
A. Onset and Location
B. Aggravating/Relieving factors and Timing **[CORRECT]**
C. Character and Severity
D. Duration and Radiation
Correct Answer: B | Rationale: Aggravating/Relieving factors and Timing are most critical because pain provoked by exertion
and relieved by rest, with relationship to activity, are hallmark features of cardiac ischemia distinguishing it from GERD,
musculoskeletal pain, or anxiety.
Q3. A diagnostic test for PE has 95% sensitivity and 40% specificity. The NP orders D-dimer for a low pre-test
probability patient. The result is negative. Which principle guides interpretation?
A. SpPin: specific positive rules in disease
B. SnNout: sensitive negative rules out disease **[CORRECT]**
C. Negative result unreliable due to low specificity
D. Test should be repeated because specificity below 50%
Correct Answer: B | Rationale: SnNout states that a test with high sensitivity, when negative, rules out disease. D-dimer with 95%
sensitivity means a negative result effectively excludes PE in low pre-test probability patients, the basis for the Wells/D-dimer PE
algorithm.
Q4. A 62-year-old presents with worst headache of life. Pre-test probability of SAH is 5%. Non-contrast head CT is
negative (98% sensitivity within 6 hours). What is the approximate post-test probability?
A. Less than 0.1% **[CORRECT]**
B. Approximately 1%
C. Approximately 5%
Page 1
, D. Approximately 10%
Correct Answer: A | Rationale: Using Bayesian reasoning, a pre-test probability of 5% with a highly sensitive negative CT (LR-
approximately 0.02) yields a post-test probability below 0.1%. However, lumbar puncture is still recommended because
consequences of missed SAH are catastrophic, showing that clinical reasoning integrates both probability and consequence.
Q5. A patient has Wells DVT score of 1 (moderate probability) and negative D-dimer. The NP concludes DVT is
ruled out without further testing. Which principle supports this?
A. Negative highly sensitive test in low-to-moderate pre-test probability excludes DVT
**[CORRECT]**
B. D-dimer has high specificity confirming absence of DVT
C. Wells score 1 indicates high probability so D-dimer should not be ordered
D. Negative D-dimer eliminates need for clinical assessment
Correct Answer: A | Rationale: D-dimer is highly sensitive, so a negative result in low-to-moderate pre-test probability (Wells 0-2)
effectively rules out DVT. For high probability (Wells 3+), D-dimer is less useful and duplex ultrasound should be obtained
directly.
Q6. Which best describes the purpose of SNAPPS in acute care NP education?
A. To replace comprehensive health history
B. To provide a learner-centered framework for case presentation promoting clinical reasoning and
differential diagnosis development **[CORRECT]**
C. To standardize EHR documentation
D. To prioritize life-threatening conditions
Correct Answer: B | Rationale: SNAPPS is a six-step learner-centered framework (Summarize, Narrow, Analyze, Probe, Plan,
Select) designed to enhance clinical reasoning during case presentations, engaging learners in differential diagnosis construction
and self-assessment of knowledge gaps.
Q7. A 45-year-old with acute abdominal pain has 30% pre-test probability of appendicitis and Alvarado score of 5.
CT with IV contrast (94% sensitivity, 95% specificity) is positive. What happens to post-test probability?
A. Decreases because Alvarado was only 5
B. Increases substantially because positive result on high-specificity test in moderate pre-test
probability raises disease likelihood **[CORRECT]**
C. Remains unchanged at 30%
D. Cannot be calculated without population prevalence
Correct Answer: B | Rationale: SpPin states a test with high specificity, when positive, rules in disease. CT with 95% specificity
(LR+ = 18.8) and a positive result in a patient with 30% pre-test probability raises post-test probability to approximately 88-90%,
demonstrating how specific tests dramatically increase diagnostic probability.
Q8. An NP conducts a focused interview with a patient with acute chest pain. The NP maintains eye contact, nods,
reflects the patients emotional state, and uses silence to allow the patient to elaborate. Which component of skilled
interviewing is being demonstrated?
A. Directive questioning
B. Active or attentive listening and connecting to the patients emotional state **[CORRECT]**
C. Biomedical data collection
D. Rapid hypothesis generation
Correct Answer: B | Rationale: Active or attentive listening involves verbal and nonverbal techniques (eye contact, nodding,
reflection, therapeutic silence) that encourage patient expression and demonstrate empathy. This is a core component of skilled
interviewing in the SNAPPS framework, essential for building rapport and obtaining accurate subjective data.
Q9. A new biomarker for sepsis has a sensitivity of 85% and specificity of 80% in an ICU population with 40%
sepsis prevalence. What is the expected positive predictive value (PPV) compared to the same test applied to an ED
population with 10% prevalence?
, A. PPV will be higher in the ED population
B. PPV will be lower in the ED population **[CORRECT]**
C. PPV will be identical in both populations
D. PPV depends only on sensitivity and specificity, not prevalence
Correct Answer: B | Rationale: PPV is directly influenced by disease prevalence; it increases as prevalence increases and
decreases as prevalence decreases. In the ICU (40% prevalence), PPV will be substantially higher than in the ED (10%
prevalence), even though the test characteristics are identical. This is why the same test can be more useful in a referral population
than in a screening population.
Q10. A diagnostic test for acute appendicitis has a positive likelihood ratio (LR+) of 12. The pre-test probability of
appendicitis is 25%. After a positive test result, the post-test probability is approximately 80%. What does the LR+ of
12 indicate?
A. The test is 12 times more likely to be negative in patients with appendicitis
B. A positive result is 12 times more likely in a patient with appendicitis than without it
**[CORRECT]**
C. The test has a 12% false positive rate
D. The test correctly identifies 88% of patients with appendicitis
Correct Answer: B | Rationale: LR+ equals sensitivity divided by (1 minus specificity). An LR+ of 12 means a positive test result
is 12 times more likely in a patient who has the disease compared to one without it. LR+ greater than 10 is considered strong
evidence for ruling in a diagnosis. This is distinct from sensitivity, specificity, and PPV, though it relates to all three.
Q11. A 55-year-old presents with acute dyspnea and pleuritic chest pain. The NP notes tachycardia (HR 112),
hypoxia (SpO2 88%), and unilateral left leg swelling. The NP also notes absence of fever and normal breath sounds.
Which findings are pertinent positives and pertinent negatives for pulmonary embolism, respectively?
A. Tachycardia and hypoxia are pertinent positives; fever absence and normal breath sounds are
pertinent negatives **[CORRECT]**
B. Pleuritic chest pain and tachycardia are pertinent positives; SpO2 of 88% is a pertinent negative
C. Unilateral leg swelling is the only pertinent positive; all others are pertinent negatives
D. There are no pertinent negatives in this presentation
Correct Answer: A | Rationale: Pertinent positives are findings that support a specific diagnosis (tachycardia, hypoxia, pleuritic
chest pain, and leg swelling support PE). Pertinent negatives are expected findings that are absent, helping to rule out alternative
diagnoses (absence of fever and normal breath sounds make pneumonia less likely). Distinguishing these is fundamental to
differential diagnosis construction in acute care.
Q12. A negative likelihood ratio (LR-) of 0.1 for a diagnostic test of heart failure using NT-proBNP is reported.
What does this value indicate?
A. A negative test result reduces the odds of heart failure by 90%
B. A negative result is only 10% as likely in a patient with heart failure compared to one without
**[CORRECT]**
C. The test has 90% specificity
D. The false negative rate is 10%
Correct Answer: B | Rationale: LR- equals (1 minus sensitivity) divided by specificity. An LR- of 0.1 means a negative result is
only one-tenth as likely in a patient with the disease compared to one without the disease. An LR- less than 0.1 is considered strong
evidence for ruling out a diagnosis (SnNout equivalent). This is particularly useful for NT-proBNP, where very low values
effectively exclude heart failure.
Q13. A patient presents with acute dyspnea, tachycardia, and hypoxia. The NP constructs a differential including PE,
pneumonia, COPD exacerbation, pneumothorax, and heart failure. Which approach best describes this process?
A. Pattern recognition only
B. Hypothesis generation creating a comprehensive differential that can be systematically tested and
refined **[CORRECT]**
