1
NR 511 MIDTERM REVIEW EXAM 2026/2027 |
Differential Diagnosis & Primary Care Practicum |
Grade A 100% Correct | Verified Answers | Pass
Guaranteed - A+ Graded
Section 1: Clinical Decision Making & Diagnostic Strategies (Q1-14)
Q1. A 42-year-old patient presents with fatigue. The nurse practitioner estimates the
pretest probability of anemia at 30%. The hemoglobin test has a sensitivity of 95%
and specificity of 90%. If the test is positive, which statement best describes the
effect on diagnostic certainty?
A. The posttest probability is approximately 80% because the positive likelihood ratio
is 9.5
B. The posttest probability remains near 30% because the test is highly sensitive
C. The posttest probability decreases to approximately 5% due to the positive result
D. The posttest probability is approximately 50% because sensitivity and specificity
are nearly equal
Correct Answer: A. The posttest probability is approximately 80% because the
positive likelihood ratio is 9.5 [CORRECT]
Rationale: LR+ = sensitivity/(1-specificity) = 0.95/0.10 = 9.5. Applying Bayes'
theorem or nomogram, a pretest probability of 30% with LR+ of 9.5 yields a posttest
probability near 80%. Most common midterm error: Selecting D, confusing
sensitivity/specificity balance with likelihood ratio impact. Recall: LR+ >10
significantly increases probability; LR+ 5-10 moderately increases.
Q2. A 28-year-old with sore throat has no cough, tender anterior cervical nodes,
tonsillar exudates, and no fever history. Centor score is 2. What is the next best step?
A. Immediate antibiotic therapy with amoxicillin
B. Rapid antigen detection test (RADT) and treat if positive
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C. Throat culture only without RADT
D. Supportive care with follow-up in 48 hours
Correct Answer: B. Rapid antigen detection test (RADT) and treat if positive
[CORRECT]
Rationale: Centor score 2-3 indicates moderate probability of Group A Strep; current
guidelines recommend RADT. If RADT positive, treat; if negative in adults, no further
testing needed. Most common midterm error: Selecting A—antibiotics should not
be given empirically without testing at this Centor threshold (treat empirically only if
score ≥4 or high prevalence).
Q3. Which test characteristic is defined as the proportion of patients WITH disease
who test positive?
A. Specificity
B. Positive predictive value
C. Sensitivity
D. Negative predictive value
Correct Answer: C. Sensitivity [CORRECT]
Rationale: Sensitivity = true positives/(true positives + false negatives), representing
detection of disease in those who have it. Most common midterm error: Confusing
sensitivity with PPV—PPV describes probability of disease given a positive test, not
test detection capability.
Q4. A 55-year-old with chest pain has a negative high-sensitivity troponin at 0 and 3
hours, normal ECG, and Wells score of 1.5. What is the most appropriate next action?
A. CT pulmonary angiography immediately
B. D-dimer testing
C. Begin therapeutic anticoagulation
D. Reassurance and discharge with no further testing
,3
Correct Answer: B. D-dimer testing [CORRECT]
Rationale: Wells score ≤4 indicates intermediate probability for PE; D-dimer is
appropriate next step to rule out. If D-dimer negative, PE is effectively excluded.
Most common midterm error: Selecting A—CTPA is reserved for high probability or
positive D-dimer, not intermediate probability without D-dimer first.
Q5. A screening test for colon cancer has 90% sensitivity and 95% specificity in a
population with 2% prevalence. What is the approximate positive predictive value?
A. 2%
B. 10%
C. 27%
D. 90%
Correct Answer: C. 27% [CORRECT]
Rationale: PPV = true positives/(true positives + false positives). In 1000 people: 20
have cancer (18 true positive), 980 don't (49 false positive). PPV = 18/(18+49) ≈ 27%.
Most common midterm error: Selecting D—confusing sensitivity with PPV. Low
prevalence dramatically reduces PPV even with good specificity.
Q6. A patient with suspected DVT has a Wells score of 5. What is the appropriate
diagnostic approach?
A. D-dimer to rule out DVT
B. Compression ultrasound without D-dimer
C. CT venography first line
D. Begin anticoagulation empirically
Correct Answer: B. Compression ultrasound without D-dimer [CORRECT]
Rationale: Wells score ≥2 indicates high probability; D-dimer is NOT useful in high
probability (will be falsely elevated). Proceed directly to compression ultrasound.
, 4
Most common midterm error: Selecting A—D-dimer is only for low/intermediate
probability to rule out, not high probability.
Q7. Which of the following is a characteristic of a test with high specificity?
A. Few false negatives
B. Few false positives
C. High negative predictive value in low prevalence
D. High sensitivity
Correct Answer: B. Few false positives [CORRECT]
Rationale: Specificity = true negatives/(true negatives + false positives); high
specificity means the test rarely labels healthy people as diseased (few false
positives). Most common midterm error: Selecting A—describes high sensitivity, not
specificity.
Q8. A 38-year-old presents with sudden severe headache ("thunderclap") reaching
maximum intensity in 60 seconds. She is afebrile with normal neurologic exam. What
is the priority action?
A. Administer sumatriptan and monitor
B. Order non-contrast head CT immediately
C. Begin antibiotics for meningitis
D. Reassure and schedule MRI in 2 weeks
Correct Answer: B. Order non-contrast head CT immediately [CORRECT]
Rationale: Thunderclap headache is a red flag for subarachnoid hemorrhage. Non-
contrast head CT is the initial imaging of choice (sensitivity >95% within 6 hours).
Most common midterm error: Selecting A—triptans are contraindicated in
thunderclap/secondary headaches. Never treat red flag headaches symptomatically
without imaging.
NR 511 MIDTERM REVIEW EXAM 2026/2027 |
Differential Diagnosis & Primary Care Practicum |
Grade A 100% Correct | Verified Answers | Pass
Guaranteed - A+ Graded
Section 1: Clinical Decision Making & Diagnostic Strategies (Q1-14)
Q1. A 42-year-old patient presents with fatigue. The nurse practitioner estimates the
pretest probability of anemia at 30%. The hemoglobin test has a sensitivity of 95%
and specificity of 90%. If the test is positive, which statement best describes the
effect on diagnostic certainty?
A. The posttest probability is approximately 80% because the positive likelihood ratio
is 9.5
B. The posttest probability remains near 30% because the test is highly sensitive
C. The posttest probability decreases to approximately 5% due to the positive result
D. The posttest probability is approximately 50% because sensitivity and specificity
are nearly equal
Correct Answer: A. The posttest probability is approximately 80% because the
positive likelihood ratio is 9.5 [CORRECT]
Rationale: LR+ = sensitivity/(1-specificity) = 0.95/0.10 = 9.5. Applying Bayes'
theorem or nomogram, a pretest probability of 30% with LR+ of 9.5 yields a posttest
probability near 80%. Most common midterm error: Selecting D, confusing
sensitivity/specificity balance with likelihood ratio impact. Recall: LR+ >10
significantly increases probability; LR+ 5-10 moderately increases.
Q2. A 28-year-old with sore throat has no cough, tender anterior cervical nodes,
tonsillar exudates, and no fever history. Centor score is 2. What is the next best step?
A. Immediate antibiotic therapy with amoxicillin
B. Rapid antigen detection test (RADT) and treat if positive
,2
C. Throat culture only without RADT
D. Supportive care with follow-up in 48 hours
Correct Answer: B. Rapid antigen detection test (RADT) and treat if positive
[CORRECT]
Rationale: Centor score 2-3 indicates moderate probability of Group A Strep; current
guidelines recommend RADT. If RADT positive, treat; if negative in adults, no further
testing needed. Most common midterm error: Selecting A—antibiotics should not
be given empirically without testing at this Centor threshold (treat empirically only if
score ≥4 or high prevalence).
Q3. Which test characteristic is defined as the proportion of patients WITH disease
who test positive?
A. Specificity
B. Positive predictive value
C. Sensitivity
D. Negative predictive value
Correct Answer: C. Sensitivity [CORRECT]
Rationale: Sensitivity = true positives/(true positives + false negatives), representing
detection of disease in those who have it. Most common midterm error: Confusing
sensitivity with PPV—PPV describes probability of disease given a positive test, not
test detection capability.
Q4. A 55-year-old with chest pain has a negative high-sensitivity troponin at 0 and 3
hours, normal ECG, and Wells score of 1.5. What is the most appropriate next action?
A. CT pulmonary angiography immediately
B. D-dimer testing
C. Begin therapeutic anticoagulation
D. Reassurance and discharge with no further testing
,3
Correct Answer: B. D-dimer testing [CORRECT]
Rationale: Wells score ≤4 indicates intermediate probability for PE; D-dimer is
appropriate next step to rule out. If D-dimer negative, PE is effectively excluded.
Most common midterm error: Selecting A—CTPA is reserved for high probability or
positive D-dimer, not intermediate probability without D-dimer first.
Q5. A screening test for colon cancer has 90% sensitivity and 95% specificity in a
population with 2% prevalence. What is the approximate positive predictive value?
A. 2%
B. 10%
C. 27%
D. 90%
Correct Answer: C. 27% [CORRECT]
Rationale: PPV = true positives/(true positives + false positives). In 1000 people: 20
have cancer (18 true positive), 980 don't (49 false positive). PPV = 18/(18+49) ≈ 27%.
Most common midterm error: Selecting D—confusing sensitivity with PPV. Low
prevalence dramatically reduces PPV even with good specificity.
Q6. A patient with suspected DVT has a Wells score of 5. What is the appropriate
diagnostic approach?
A. D-dimer to rule out DVT
B. Compression ultrasound without D-dimer
C. CT venography first line
D. Begin anticoagulation empirically
Correct Answer: B. Compression ultrasound without D-dimer [CORRECT]
Rationale: Wells score ≥2 indicates high probability; D-dimer is NOT useful in high
probability (will be falsely elevated). Proceed directly to compression ultrasound.
, 4
Most common midterm error: Selecting A—D-dimer is only for low/intermediate
probability to rule out, not high probability.
Q7. Which of the following is a characteristic of a test with high specificity?
A. Few false negatives
B. Few false positives
C. High negative predictive value in low prevalence
D. High sensitivity
Correct Answer: B. Few false positives [CORRECT]
Rationale: Specificity = true negatives/(true negatives + false positives); high
specificity means the test rarely labels healthy people as diseased (few false
positives). Most common midterm error: Selecting A—describes high sensitivity, not
specificity.
Q8. A 38-year-old presents with sudden severe headache ("thunderclap") reaching
maximum intensity in 60 seconds. She is afebrile with normal neurologic exam. What
is the priority action?
A. Administer sumatriptan and monitor
B. Order non-contrast head CT immediately
C. Begin antibiotics for meningitis
D. Reassure and schedule MRI in 2 weeks
Correct Answer: B. Order non-contrast head CT immediately [CORRECT]
Rationale: Thunderclap headache is a red flag for subarachnoid hemorrhage. Non-
contrast head CT is the initial imaging of choice (sensitivity >95% within 6 hours).
Most common midterm error: Selecting A—triptans are contraindicated in
thunderclap/secondary headaches. Never treat red flag headaches symptomatically
without imaging.
