CBIC Epidemiology 2

Question 1

Which epidemiological measure describes the probability that a person without a disease will develop that disease over a specified time period?

Accepted Answer

Cumulative incidence

Answer

Cumulative incidence (also called incidence proportion) measures the probability of developing a disease over a defined period among those initially at risk.

Question 2

In a healthcare outbreak investigation, what is the purpose of calculating an 'epidemic curve'?

Accepted Answer

To visualize the pattern and timing of cases over time

Answer

An epidemic curve is a histogram that plots the number of cases by date of onset, revealing the pattern, magnitude, and potential source (common source vs. propagated) of an outbreak.

Question 3

A hospital reports 15 new CLABSI cases per 1,000 central line-days. This is an example of which epidemiological rate?

Accepted Answer

Specific rate

Answer

A specific rate uses a defined denominator (central line-days) that is specific to the population at risk, making it more meaningful than a crude rate for device-associated infections.

Question 4

Which concept explains why an infection control program may see an apparent increase in HAI rates after implementing better surveillance methods?

Accepted Answer

Ascertainment bias

Answer

Ascertainment bias occurs when improved detection methods identify cases that previously went unrecognized, causing an apparent rise in rates that reflects better surveillance rather than a true increase.

Question 5

In the context of HAI surveillance, what does a 'standardized infection ratio' (SIR) less than 1.0 indicate?

Accepted Answer

The facility has fewer infections than predicted

Answer

An SIR less than 1.0 means the observed number of infections is lower than the predicted number based on national benchmark data, suggesting better-than-expected performance.

CBIC - Certification Board of Infection Control Practice Test

CBIC - Certification Board of Infection Control Practice Test

CBIC Epidemiology 2