Which method is best for collecting a wound sample for culture?

• A. Tissue biopsy
• B. Blood culture
• C. Urine sample
• D. Culture Swab

Answer: (D)

Collecting a wound culture aims to sample organisms actually in the wound tissue, not just surface bacteria. A culture swab is best here because, when done with a standardized technique like the Levine method, it provides a representative sample from the wound bed with minimal invasiveness. After cleaning the wound to remove debris, rotate a sterile swab over a small area of the wound bed with enough pressure to express tissue fluid, avoiding crusts and necrotic tissue. The swab is then placed in transport medium and sent to the lab. This approach balances accuracy with patient comfort and practicality, making it preferred over superficial sampling alone.

Blood cultures target bloodstream infections, and urine samples target urinary infections, so they aren’t appropriate for diagnosing a wound infection. A tissue biopsy, while more definitive for deep or difficult infections, is more invasive and reserved for cases where a swab may not yield reliable results or if deeper tissue sampling is needed.