Associate – Infection Prevention and Control (a-IPC) Practice Exam 2026 - Free Infection Prevention Practice Questions and Study Guide

A key idea here is how test characteristics guide interpretation. Direct fluorescent antibody testing for pertussis is fast but not very sensitive, so a negative result does not rule out infection. Culture for Bordetella pertussis, on the other hand, is highly specific. A positive culture means the organism is actually present, so it confirms pertussis even when the DFA was negative. The other statements rely on incorrect assumptions about DFA sensitivity, culture timing, or culture sensitivity, whereas the positive culture clearly establishes the diagnosis given its high specificity.