CBIC Test 3 — Questions and Answers
Question 1: Which statistical test is most appropriate when comparing infection rates between two independent groups with large sample sizes?
- Chi-square test (Correct answer)
- Paired t-test
- Wilcoxon signed-rank test
- Fisher's exact test
Correct answer: Chi-square test
The chi-square test is appropriate for comparing proportions or rates between two or more independent groups when sample sizes are large.
Question 2: Under the NHSN definition, a healthcare-associated infection (HAI) is generally considered present when it occurs at least how many hours after admission?
- 24 hours
- 48 hours (Correct answer)
- 72 hours
- 96 hours
Correct answer: 48 hours
NHSN defines a healthcare-associated infection as one that occurs 48 hours or more after admission, when no evidence of infection was present at admission.
Question 3: Which element is NOT part of the chain of infection?
- Susceptible host
- Reservoir
- Vector capacity (Correct answer)
- Mode of transmission
Correct answer: Vector capacity
The chain of infection consists of infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host; 'vector capacity' is not a named link in the chain.
Question 4: A hospital experiences an increase in ventilator-associated events (VAE). Which intervention targets the most evidence-based prevention bundle element?
- Prophylactic antifungal therapy
- Daily sedation interruption and spontaneous breathing trials (Correct answer)
- Routine bronchoscopy for intubated patients
- Prophylactic prone positioning for all ventilated patients
Correct answer: Daily sedation interruption and spontaneous breathing trials
Daily sedation interruption paired with spontaneous breathing trials is a core bundle element that reduces ventilator days and associated events.
Question 5: Which personal protective equipment (PPE) sequence is correct when donning for contact and droplet precautions?
- Gown → mask → goggles → gloves (Correct answer)
- Gloves → gown → mask → goggles
- Mask → goggles → gown → gloves
- Goggles → mask → gloves → gown
Correct answer: Gown → mask → goggles → gloves
CDC guidance specifies donning in the order gown, mask/respirator, goggles/face shield, then gloves so that gloves cover gown cuffs and are the last item to be donned.
Question 6: Which bloodborne pathogen has the highest risk of transmission following a needlestick injury from an infected source?
- HIV
- Hepatitis C virus (HCV)
- Hepatitis B virus (HBV) (Correct answer)
- HTLV-1
Correct answer: Hepatitis B virus (HBV)
HBV has a transmission risk of approximately 6–30% per needlestick from an HBeAg-positive source, far higher than HCV (~1.8%) or HIV (~0.3%).
Question 7: An outbreak investigation reveals that the epidemic curve has a single sharp peak. This pattern is most consistent with which type of outbreak?
- Propagated source outbreak
- Common source point-source outbreak (Correct answer)
- Mixed outbreak
- Continuous common source outbreak
Correct answer: Common source point-source outbreak
A single sharp peak on an epidemic curve indicates a point-source outbreak where most cases were exposed to the same source during a brief period.
CBIC Test 3
Which statistical test is most appropriate when comparing infection rates between two independent groups with large sample sizes?