In adults, procalcitonin-guided antibiotic therapy has been shown to reduce:

• A. Antibiotic exposure
• B. Cost
• C. Hospital stay
• D. Mortality

Answer: (A)

Using procalcitonin as a guide helps tailor antibiotic use by differentiating bacterial from non-bacterial illness and by signaling when antibiotics can be stopped early. When procalcitonin levels are low or quickly decline with treatment, this suggests a lower likelihood of bacterial infection or a good response to therapy, so clinicians are more confident stopping antibiotics sooner. This approach has been shown in adults to reduce overall antibiotic exposure—fewer days on antibiotics and a smaller share of patients receiving antibiotics—without compromising safety or increasing mortality. Evidence for other outcomes like cost, length of hospital stay, or mortality is less consistent, so the most reliably demonstrated benefit is reduced antibiotic exposure.