NR511 / NR 511 Midterm Exam (Weeks 1–4)
2026–2027 | Differential Diagnosis & Primary
Care Practicum | Chamberlain
Topic 1: Clinical Decision-Making & Diagnostic Reasoning
1. What is the first step in diagnostic reasoning when a patient presents with symptoms?
Generate a differential diagnosis based on history and risk factorsRationale: Start broad
with possible causes, then narrow using targeted questions, exam, and tests.
2. Sensitivity vs. specificity: Which is best for ruling out disease? High sensitivity (SnNOut:
Sensitive test negative rules out disease)Rationale: Sensitive tests catch most true
positives; few false negatives.
3. Which test is best for ruling in disease? High specificity (SpPIn: Specific test positive
rules in disease)Rationale: Specific tests have few false positives; positive result strongly
confirms.
4. Positive predictive value depends on: Disease prevalence in the populationRationale:
Higher prevalence → higher PPV even with same test characteristics.
5. Likelihood ratio >1 indicates: Test increases probability of diseaseRationale: LR+ >10
strongly increases likelihood; LR- <0.1 strongly decreases.
Topic 2: Evidence-Based Practice & Screening
6. USPSTF Grade A recommendation means: High certainty of substantial net benefit –
strongly recommendRationale: Providers should offer/provide this service.
7. Grade D recommendation means: Discourage use – moderate/high certainty of no net
benefit or harm outweighs benefitRationale: Actively advise against the service.
, 8. What is the goal of screening tests? Detect disease early in asymptomatic people to
reduce morbidity/mortalityRationale: Must be acceptable, accurate, and lead to
improved outcomes.
9. Lead time bias in screening means: Earlier diagnosis makes survival appear longer
without changing outcomeRationale: Common pitfall in evaluating screening
effectiveness.
10. Overdiagnosis bias: Detecting disease that would never cause symptoms or
deathRationale: Leads to unnecessary treatment and anxiety.
Topic 3: Common Respiratory Disorders
11. Classic presentation of acute bacterial rhinosinusitis: Symptoms >10 days without
improvement OR worsening after initial improvement OR severe symptoms ≥3-4
daysRationale: IDSA criteria distinguish from viral; antibiotics indicated.
12. First-line treatment for uncomplicated acute bacterial sinusitis: Amoxicillin-clavulanate
(high-dose)Rationale: Covers resistant S. pneumoniae and H. influenzae.
13. Centor criteria for strep pharyngitis – score ≥3: Treat empirically or test and treat if
positiveRationale: High likelihood of GABHS; rapid antigen or culture.
14. Most common cause of community-acquired pneumonia in adults: Streptococcus
pneumoniaeRationale: Even in era of PCV13 vaccine.
15. Outpatient treatment for healthy adult with CAP (CURB-65 ≤1): Macrolide
(azithromycin) OR doxycyclineRationale: Covers typical (S. pneumo) and atypical
(Mycoplasma, Chlamydia).
2026–2027 | Differential Diagnosis & Primary
Care Practicum | Chamberlain
Topic 1: Clinical Decision-Making & Diagnostic Reasoning
1. What is the first step in diagnostic reasoning when a patient presents with symptoms?
Generate a differential diagnosis based on history and risk factorsRationale: Start broad
with possible causes, then narrow using targeted questions, exam, and tests.
2. Sensitivity vs. specificity: Which is best for ruling out disease? High sensitivity (SnNOut:
Sensitive test negative rules out disease)Rationale: Sensitive tests catch most true
positives; few false negatives.
3. Which test is best for ruling in disease? High specificity (SpPIn: Specific test positive
rules in disease)Rationale: Specific tests have few false positives; positive result strongly
confirms.
4. Positive predictive value depends on: Disease prevalence in the populationRationale:
Higher prevalence → higher PPV even with same test characteristics.
5. Likelihood ratio >1 indicates: Test increases probability of diseaseRationale: LR+ >10
strongly increases likelihood; LR- <0.1 strongly decreases.
Topic 2: Evidence-Based Practice & Screening
6. USPSTF Grade A recommendation means: High certainty of substantial net benefit –
strongly recommendRationale: Providers should offer/provide this service.
7. Grade D recommendation means: Discourage use – moderate/high certainty of no net
benefit or harm outweighs benefitRationale: Actively advise against the service.
, 8. What is the goal of screening tests? Detect disease early in asymptomatic people to
reduce morbidity/mortalityRationale: Must be acceptable, accurate, and lead to
improved outcomes.
9. Lead time bias in screening means: Earlier diagnosis makes survival appear longer
without changing outcomeRationale: Common pitfall in evaluating screening
effectiveness.
10. Overdiagnosis bias: Detecting disease that would never cause symptoms or
deathRationale: Leads to unnecessary treatment and anxiety.
Topic 3: Common Respiratory Disorders
11. Classic presentation of acute bacterial rhinosinusitis: Symptoms >10 days without
improvement OR worsening after initial improvement OR severe symptoms ≥3-4
daysRationale: IDSA criteria distinguish from viral; antibiotics indicated.
12. First-line treatment for uncomplicated acute bacterial sinusitis: Amoxicillin-clavulanate
(high-dose)Rationale: Covers resistant S. pneumoniae and H. influenzae.
13. Centor criteria for strep pharyngitis – score ≥3: Treat empirically or test and treat if
positiveRationale: High likelihood of GABHS; rapid antigen or culture.
14. Most common cause of community-acquired pneumonia in adults: Streptococcus
pneumoniaeRationale: Even in era of PCV13 vaccine.
15. Outpatient treatment for healthy adult with CAP (CURB-65 ≤1): Macrolide
(azithromycin) OR doxycyclineRationale: Covers typical (S. pneumo) and atypical
(Mycoplasma, Chlamydia).
