What is the clinical impact of a false-negative result from a rapid diagnostic test?

• A. Delayed targeted therapy and potential worse outcomes.
• B. Immediate targeted therapy.
• C. No impact.
• D. Faster time to de-escalation.

Answer: (A)

A false-negative rapid diagnostic test delays the opportunity to tailor therapy to the actual pathogen. When the test misses the organism or its resistance, clinicians continue with empiric or broad-spectrum antibiotics rather than switching promptly to the most effective, targeted therapy. That delay can allow the infection to progress, worsen clinical outcomes, and extend hospitalization, especially in severe or high-risk infections. It also hampers antimicrobial stewardship efforts, since de-escalation or narrowing therapy typically relies on confirming the specific pathogen and its susceptibilities.

In other words, a false-negative does not prompt immediate targeted treatment; it keeps patients on less optimal therapy longer. It also does not accelerate de-escalation, because you lack the definitive pathogen information to safely narrow therapy. Conversely, a true positive would enable rapid, targeted treatment, improving outcomes.