NR569 Final Exam | Differential Diagnosis in Acute Care | Chamberlain University 2026/2027
NR569 Final Exam
Differential Diagnosis in Acute Care Practicum
Chamberlain University | 2026/2027 Update | 100% Correct
100 Questions | 9 Sections | Verified Answers
Section 1: Clinical Reasoning and Diagnostic Frameworks (SNAPPS, OLDCARTS,
Diagnostic Accuracy)
Q1: The acute care nurse practitioner is precepting a student who presents a patient case using the SNAPPS
framework. The student states, 'I think the patient has community-acquired pneumonia.' Which component of the
SNAPPS model does this statement represent?
A. Summarize the history and findings
B. Narrow the differential to two or three diagnoses **[CORRECT]**
C. Analyze the differential by comparing and contrasting
D. Probe the preceptor for uncertainties or knowledge gaps
Correct Answer: B
Rationale: The 'N' in SNAPPS stands for 'Narrow the differential to two or three diagnoses.' When the student verbalizes a
specific diagnostic impression such as community-acquired pneumonia, they are narrowing the differential list. The S stands for
Summarize, A for Analyze, the second P for Probe, P for Plan, and S for Select a case-related issue for self-directed learning.
Q2: A nurse practitioner uses the OLDCARTS mnemonic to obtain a symptom history from a patient presenting
with acute dyspnea. Which element of OLDCARTS is being assessed when the NP asks, 'Did the shortness of
breath begin suddenly or gradually?'
A. Onset **[CORRECT]**
B. Location
C. Duration
D. Timing
Correct Answer: A
Rationale: The 'O' in OLDCARTS stands for Onset, which refers to how and when the symptom began. Asking whether the
dyspnea was sudden or gradual helps characterize the onset. Sudden onset suggests conditions like pulmonary embolism or
pneumothorax, while gradual onset may indicate CHF exacerbation, pneumonia, or anemia. Location (L) refers to where the
symptom is felt, Duration (D) is how long it lasts, and Timing (T) refers to pattern or relationship to time of day.
Q3: A diagnostic test for pulmonary embolism has a sensitivity of 95% and a specificity of 85%. The NP
understands that a negative result on this test most accurately rules out pulmonary embolism in which clinical
scenario?
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,NR569 Final Exam | Differential Diagnosis in Acute Care | Chamberlain University 2026/2027
A. High pretest probability
B. Low pretest probability **[CORRECT]**
C. Moderate pretest probability
D. Any pretest probability
Correct Answer: B
Rationale: SNOUT is the mnemonic: a test with high Sensitivity and Negative result rules OUT the disease (SNout). With 95%
sensitivity, a negative result is very reliable for ruling out PE. This is most useful when pretest probability is low, because the
negative result combined with low prior probability makes PE extremely unlikely. With high pretest probability, even a negative
result may not be sufficient to exclude PE due to the higher prior likelihood of disease.
Q4: A 52-year-old male presents with acute chest pain. The pretest probability of acute coronary syndrome (ACS)
is estimated at 20%. A highly sensitive troponin assay has a sensitivity of 99% and specificity of 90% for detecting
ACS. The troponin result is negative. Using Bayes' theorem concepts, what is the most accurate interpretation?
A. ACS is definitively ruled out
B. The posttest probability of ACS is significantly reduced but not eliminated **[CORRECT]**
C. The posttest probability of ACS is unchanged from pretest probability
D. ACS is now more likely than before the test
Correct Answer: B
Rationale: A negative result on a highly sensitive test (99% sensitivity) substantially reduces but does not eliminate the probability
of disease, especially when pretest probability is moderate (20%). The negative likelihood ratio (1 - sensitivity / specificity) for this
test would be approximately 0.011, which significantly lowers posttest probability, but clinical judgment and possibly serial testing
are still warranted. ACS can never be definitively ruled out by a single negative troponin, as early presentations may not yet show
elevation.
Q5: The nurse practitioner is teaching a student about SPIN and SNOUT mnemonics. Which of the following
test-characteristic combinations correctly applies the SPIN rule?
A. A D-dimer with high sensitivity and a positive result rules in deep vein thrombosis
B. A high-sensitivity troponin with a negative result rules out myocardial infarction
C. A chest X-ray with high specificity and a positive result rules in pneumonia **[CORRECT]**
D. A urinalysis with high sensitivity and a negative result rules out urinary tract infection
Correct Answer: C
Rationale: SPIN stands for high Specificity and Positive result rules IN the disease. A chest X-ray with high specificity for
pneumonia, when positive, strongly supports the diagnosis. Option A describes a high-sensitivity test (D-dimer) with a positive
result, which does not effectively rule in DVT due to lower specificity. Options B and D both describe SNOUT scenarios where a
negative result on a sensitive test rules out disease.
Q6: During a case presentation using the SNAPPS model, the student asks the preceptor, 'I am unsure whether this
patient's pleuritic chest pain and elevated D-dimer warrant CT angiography or whether we should pursue other
testing first.' Which component of SNAPPS does this question represent?
A. Summarize
B. Narrow
C. Analyze
D. Probe **[CORRECT]**
Correct Answer: D
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,NR569 Final Exam | Differential Diagnosis in Acute Care | Chamberlain University 2026/2027
Rationale: The 'P' in SNAPPS stands for 'Probe the preceptor for uncertainties or knowledge gaps.' When the student expresses
uncertainty about the next diagnostic step (CT angiography vs. other testing), they are probing for guidance. This is a critical
component of SNAPPS that promotes dialogue between learner and preceptor and identifies areas where the learner needs
additional knowledge.
Q7: A 45-year-old female presents with fatigue, weight gain, and cold intolerance. The NP suspects
hypothyroidism and orders a TSH. The test has a sensitivity of 98% and specificity of 92% for primary
hypothyroidism. The TSH is elevated at 12 mIU/L. What is the most appropriate interpretation using diagnostic
accuracy principles?
A. The elevated TSH is a false positive given the moderate pretest probability
B. The positive result on a test with 92% specificity significantly increases the probability of
hypothyroidism **[CORRECT]**
C. A confirmatory test with higher specificity is needed before any treatment
D. The sensitivity of the test is more relevant than specificity for this positive result
Correct Answer: B
Rationale: For a positive result, specificity is the key characteristic. A test with 92% specificity has a low false positive rate (8%),
meaning a positive result is highly likely to be a true positive. Combined with clinical findings (fatigue, weight gain, cold
intolerance) that raise pretest probability, the positive TSH significantly increases posttest probability of hypothyroidism. While
confirmatory free T4 is often ordered, the elevated TSH alone is strongly diagnostic. Sensitivity is more relevant when interpreting
negative results.
Q8: The NP is evaluating a patient with acute abdominal pain and uses the concept of likelihood ratios. A positive
ultrasonographic finding for cholecystitis has a positive likelihood ratio (LR+) of 12.4. Which interpretation is
correct?
A. A patient with a positive ultrasound is 12.4 times more likely to have cholecystitis than a patient without
cholecystitis
B. The test correctly identifies 12.4% of patients with cholecystitis
C. The false positive rate of the ultrasound is 12.4%
D. A positive ultrasound result increases the odds of cholecystitis by 12.4-fold compared to the pretest
odds **[CORRECT]**
Correct Answer: D
Rationale: A positive likelihood ratio (LR+) of 12.4 means that a positive ultrasound result is 12.4 times more likely to occur in a
patient who actually has cholecystitis than in a patient who does not. Mathematically, LR+ = Sensitivity / (1 - Specificity). An
LR+ greater than 10 is considered strong evidence for ruling in the diagnosis. It increases the pretest odds by a factor of 12.4 to
generate posttest odds, which can then be converted to posttest probability.
Q9: During SNAPPS presentation, the student summarizes the pertinent positives and negatives from the history
and physical examination. Which of the following best exemplifies a pertinent negative in a patient being
evaluated for heart failure?
A. Bilateral lower extremity edema
B. Jugular venous distension
C. Absence of orthopnea and paroxysmal nocturnal dyspnea **[CORRECT]**
D. Crackles on lung auscultation
Correct Answer: C
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, NR569 Final Exam | Differential Diagnosis in Acute Care | Chamberlain University 2026/2027
Rationale: A pertinent negative is a finding that, by its absence, helps narrow the differential diagnosis. The absence of
orthopnea and paroxysmal nocturnal dyspnea (PND) in a patient being evaluated for heart failure is a pertinent negative because
these are classic symptoms of heart failure, and their absence makes the diagnosis less likely. Bilateral edema, JVD, and crackles
are all pertinent positives that support the diagnosis of heart failure.
Q10: A nurse practitioner is considering pretest probability for a patient with suspected acute coronary syndrome.
Which clinical decision rule is most appropriate for estimating pretest probability in this scenario?
A. Wells criteria for pulmonary embolism
B. HEART score **[CORRECT]**
C. CHA2DS2-VASc score
D. CURB-65 score
Correct Answer: B
Rationale: The HEART score (History, ECG, Age, Risk factors, Troponin) is a clinical decision rule specifically designed to
estimate pretest probability of acute coronary syndrome in patients presenting with chest pain. It categorizes patients into low,
moderate, and high risk, guiding disposition and workup intensity. Wells criteria is for PE, CHA2DS2-VASc is for stroke risk in
atrial fibrillation, and CURB-65 is for mortality risk in pneumonia.
Q11: The NP is teaching about the 'A' component of the SNAPPS model: Analyze the differential diagnosis.
Which statement by the student demonstrates correct understanding of this component?
A. 'I will list all possible diagnoses no matter how unlikely they are'
B. 'I will compare and contrast the remaining diagnoses by discussing how each fits or does not fit the
clinical picture' **[CORRECT]**
C. 'I will order every test available to rule out all possible conditions'
D. 'I will present only the most likely diagnosis and skip less likely alternatives'
Correct Answer: B
Rationale: The Analyze component of SNAPPS requires the learner to compare and contrast the remaining differential
diagnoses, discussing how each diagnosis either fits or does not fit the clinical presentation. This involves critical reasoning about
which findings support or argue against each diagnosis. Simply listing all possible diagnoses without analysis does not fulfill this
component, nor does skipping less likely alternatives or ordering indiscriminate testing.
Q12: A 35-year-old female presents with right lower quadrant abdominal pain. The NP estimates a pretest
probability of 30% for acute appendicitis. A CT scan of the abdomen and pelvis has a sensitivity of 94% and
specificity of 95% for appendicitis. If the CT is positive, which statement best describes the posttest probability?
A. The posttest probability is approximately 90%, strongly supporting the diagnosis **[CORRECT]**
B. The posttest probability remains at 30% because CT cannot change pretest probability
C. The posttest probability decreases because false positives are common with CT
D. The posttest probability is approximately 50%, requiring additional testing
Correct Answer: A
Rationale: Using the Fagan nomogram approach: with a pretest probability of 30% (pretest odds = 0.43) and a positive
likelihood ratio of Sensitivity/(1-Specificity) = 0.94/0.05 = 18.8, the posttest odds = 0.43 x 18.8 = 8.07, yielding a posttest
probability of approximately 89-91%. A CT with 94% sensitivity and 95% specificity is an excellent diagnostic test, and a positive
result in a patient with moderate pretest probability makes the diagnosis highly likely.
Page 4
NR569 Final Exam
Differential Diagnosis in Acute Care Practicum
Chamberlain University | 2026/2027 Update | 100% Correct
100 Questions | 9 Sections | Verified Answers
Section 1: Clinical Reasoning and Diagnostic Frameworks (SNAPPS, OLDCARTS,
Diagnostic Accuracy)
Q1: The acute care nurse practitioner is precepting a student who presents a patient case using the SNAPPS
framework. The student states, 'I think the patient has community-acquired pneumonia.' Which component of the
SNAPPS model does this statement represent?
A. Summarize the history and findings
B. Narrow the differential to two or three diagnoses **[CORRECT]**
C. Analyze the differential by comparing and contrasting
D. Probe the preceptor for uncertainties or knowledge gaps
Correct Answer: B
Rationale: The 'N' in SNAPPS stands for 'Narrow the differential to two or three diagnoses.' When the student verbalizes a
specific diagnostic impression such as community-acquired pneumonia, they are narrowing the differential list. The S stands for
Summarize, A for Analyze, the second P for Probe, P for Plan, and S for Select a case-related issue for self-directed learning.
Q2: A nurse practitioner uses the OLDCARTS mnemonic to obtain a symptom history from a patient presenting
with acute dyspnea. Which element of OLDCARTS is being assessed when the NP asks, 'Did the shortness of
breath begin suddenly or gradually?'
A. Onset **[CORRECT]**
B. Location
C. Duration
D. Timing
Correct Answer: A
Rationale: The 'O' in OLDCARTS stands for Onset, which refers to how and when the symptom began. Asking whether the
dyspnea was sudden or gradual helps characterize the onset. Sudden onset suggests conditions like pulmonary embolism or
pneumothorax, while gradual onset may indicate CHF exacerbation, pneumonia, or anemia. Location (L) refers to where the
symptom is felt, Duration (D) is how long it lasts, and Timing (T) refers to pattern or relationship to time of day.
Q3: A diagnostic test for pulmonary embolism has a sensitivity of 95% and a specificity of 85%. The NP
understands that a negative result on this test most accurately rules out pulmonary embolism in which clinical
scenario?
Page 1
,NR569 Final Exam | Differential Diagnosis in Acute Care | Chamberlain University 2026/2027
A. High pretest probability
B. Low pretest probability **[CORRECT]**
C. Moderate pretest probability
D. Any pretest probability
Correct Answer: B
Rationale: SNOUT is the mnemonic: a test with high Sensitivity and Negative result rules OUT the disease (SNout). With 95%
sensitivity, a negative result is very reliable for ruling out PE. This is most useful when pretest probability is low, because the
negative result combined with low prior probability makes PE extremely unlikely. With high pretest probability, even a negative
result may not be sufficient to exclude PE due to the higher prior likelihood of disease.
Q4: A 52-year-old male presents with acute chest pain. The pretest probability of acute coronary syndrome (ACS)
is estimated at 20%. A highly sensitive troponin assay has a sensitivity of 99% and specificity of 90% for detecting
ACS. The troponin result is negative. Using Bayes' theorem concepts, what is the most accurate interpretation?
A. ACS is definitively ruled out
B. The posttest probability of ACS is significantly reduced but not eliminated **[CORRECT]**
C. The posttest probability of ACS is unchanged from pretest probability
D. ACS is now more likely than before the test
Correct Answer: B
Rationale: A negative result on a highly sensitive test (99% sensitivity) substantially reduces but does not eliminate the probability
of disease, especially when pretest probability is moderate (20%). The negative likelihood ratio (1 - sensitivity / specificity) for this
test would be approximately 0.011, which significantly lowers posttest probability, but clinical judgment and possibly serial testing
are still warranted. ACS can never be definitively ruled out by a single negative troponin, as early presentations may not yet show
elevation.
Q5: The nurse practitioner is teaching a student about SPIN and SNOUT mnemonics. Which of the following
test-characteristic combinations correctly applies the SPIN rule?
A. A D-dimer with high sensitivity and a positive result rules in deep vein thrombosis
B. A high-sensitivity troponin with a negative result rules out myocardial infarction
C. A chest X-ray with high specificity and a positive result rules in pneumonia **[CORRECT]**
D. A urinalysis with high sensitivity and a negative result rules out urinary tract infection
Correct Answer: C
Rationale: SPIN stands for high Specificity and Positive result rules IN the disease. A chest X-ray with high specificity for
pneumonia, when positive, strongly supports the diagnosis. Option A describes a high-sensitivity test (D-dimer) with a positive
result, which does not effectively rule in DVT due to lower specificity. Options B and D both describe SNOUT scenarios where a
negative result on a sensitive test rules out disease.
Q6: During a case presentation using the SNAPPS model, the student asks the preceptor, 'I am unsure whether this
patient's pleuritic chest pain and elevated D-dimer warrant CT angiography or whether we should pursue other
testing first.' Which component of SNAPPS does this question represent?
A. Summarize
B. Narrow
C. Analyze
D. Probe **[CORRECT]**
Correct Answer: D
Page 2
,NR569 Final Exam | Differential Diagnosis in Acute Care | Chamberlain University 2026/2027
Rationale: The 'P' in SNAPPS stands for 'Probe the preceptor for uncertainties or knowledge gaps.' When the student expresses
uncertainty about the next diagnostic step (CT angiography vs. other testing), they are probing for guidance. This is a critical
component of SNAPPS that promotes dialogue between learner and preceptor and identifies areas where the learner needs
additional knowledge.
Q7: A 45-year-old female presents with fatigue, weight gain, and cold intolerance. The NP suspects
hypothyroidism and orders a TSH. The test has a sensitivity of 98% and specificity of 92% for primary
hypothyroidism. The TSH is elevated at 12 mIU/L. What is the most appropriate interpretation using diagnostic
accuracy principles?
A. The elevated TSH is a false positive given the moderate pretest probability
B. The positive result on a test with 92% specificity significantly increases the probability of
hypothyroidism **[CORRECT]**
C. A confirmatory test with higher specificity is needed before any treatment
D. The sensitivity of the test is more relevant than specificity for this positive result
Correct Answer: B
Rationale: For a positive result, specificity is the key characteristic. A test with 92% specificity has a low false positive rate (8%),
meaning a positive result is highly likely to be a true positive. Combined with clinical findings (fatigue, weight gain, cold
intolerance) that raise pretest probability, the positive TSH significantly increases posttest probability of hypothyroidism. While
confirmatory free T4 is often ordered, the elevated TSH alone is strongly diagnostic. Sensitivity is more relevant when interpreting
negative results.
Q8: The NP is evaluating a patient with acute abdominal pain and uses the concept of likelihood ratios. A positive
ultrasonographic finding for cholecystitis has a positive likelihood ratio (LR+) of 12.4. Which interpretation is
correct?
A. A patient with a positive ultrasound is 12.4 times more likely to have cholecystitis than a patient without
cholecystitis
B. The test correctly identifies 12.4% of patients with cholecystitis
C. The false positive rate of the ultrasound is 12.4%
D. A positive ultrasound result increases the odds of cholecystitis by 12.4-fold compared to the pretest
odds **[CORRECT]**
Correct Answer: D
Rationale: A positive likelihood ratio (LR+) of 12.4 means that a positive ultrasound result is 12.4 times more likely to occur in a
patient who actually has cholecystitis than in a patient who does not. Mathematically, LR+ = Sensitivity / (1 - Specificity). An
LR+ greater than 10 is considered strong evidence for ruling in the diagnosis. It increases the pretest odds by a factor of 12.4 to
generate posttest odds, which can then be converted to posttest probability.
Q9: During SNAPPS presentation, the student summarizes the pertinent positives and negatives from the history
and physical examination. Which of the following best exemplifies a pertinent negative in a patient being
evaluated for heart failure?
A. Bilateral lower extremity edema
B. Jugular venous distension
C. Absence of orthopnea and paroxysmal nocturnal dyspnea **[CORRECT]**
D. Crackles on lung auscultation
Correct Answer: C
Page 3
, NR569 Final Exam | Differential Diagnosis in Acute Care | Chamberlain University 2026/2027
Rationale: A pertinent negative is a finding that, by its absence, helps narrow the differential diagnosis. The absence of
orthopnea and paroxysmal nocturnal dyspnea (PND) in a patient being evaluated for heart failure is a pertinent negative because
these are classic symptoms of heart failure, and their absence makes the diagnosis less likely. Bilateral edema, JVD, and crackles
are all pertinent positives that support the diagnosis of heart failure.
Q10: A nurse practitioner is considering pretest probability for a patient with suspected acute coronary syndrome.
Which clinical decision rule is most appropriate for estimating pretest probability in this scenario?
A. Wells criteria for pulmonary embolism
B. HEART score **[CORRECT]**
C. CHA2DS2-VASc score
D. CURB-65 score
Correct Answer: B
Rationale: The HEART score (History, ECG, Age, Risk factors, Troponin) is a clinical decision rule specifically designed to
estimate pretest probability of acute coronary syndrome in patients presenting with chest pain. It categorizes patients into low,
moderate, and high risk, guiding disposition and workup intensity. Wells criteria is for PE, CHA2DS2-VASc is for stroke risk in
atrial fibrillation, and CURB-65 is for mortality risk in pneumonia.
Q11: The NP is teaching about the 'A' component of the SNAPPS model: Analyze the differential diagnosis.
Which statement by the student demonstrates correct understanding of this component?
A. 'I will list all possible diagnoses no matter how unlikely they are'
B. 'I will compare and contrast the remaining diagnoses by discussing how each fits or does not fit the
clinical picture' **[CORRECT]**
C. 'I will order every test available to rule out all possible conditions'
D. 'I will present only the most likely diagnosis and skip less likely alternatives'
Correct Answer: B
Rationale: The Analyze component of SNAPPS requires the learner to compare and contrast the remaining differential
diagnoses, discussing how each diagnosis either fits or does not fit the clinical presentation. This involves critical reasoning about
which findings support or argue against each diagnosis. Simply listing all possible diagnoses without analysis does not fulfill this
component, nor does skipping less likely alternatives or ordering indiscriminate testing.
Q12: A 35-year-old female presents with right lower quadrant abdominal pain. The NP estimates a pretest
probability of 30% for acute appendicitis. A CT scan of the abdomen and pelvis has a sensitivity of 94% and
specificity of 95% for appendicitis. If the CT is positive, which statement best describes the posttest probability?
A. The posttest probability is approximately 90%, strongly supporting the diagnosis **[CORRECT]**
B. The posttest probability remains at 30% because CT cannot change pretest probability
C. The posttest probability decreases because false positives are common with CT
D. The posttest probability is approximately 50%, requiring additional testing
Correct Answer: A
Rationale: Using the Fagan nomogram approach: with a pretest probability of 30% (pretest odds = 0.43) and a positive
likelihood ratio of Sensitivity/(1-Specificity) = 0.94/0.05 = 18.8, the posttest odds = 0.43 x 18.8 = 8.07, yielding a posttest
probability of approximately 89-91%. A CT with 94% sensitivity and 95% specificity is an excellent diagnostic test, and a positive
result in a patient with moderate pretest probability makes the diagnosis highly likely.
Page 4
