Which specimen should be sent to the lab for culture after catheter removal due to infection?

• A. Catheter tip
• B. Peripheral blood culture
• C. Urine culture
• D. Wound culture

Answer: (A)

Catheter biofilm on the device is the typical source of infection, so the most direct way to confirm catheter-related infection is to culture the catheter itself after removal. The distal end of the catheter (catheter tip) is sent to microbiology, often after a brief sonication or vortexing to dislodge organisms from the biofilm. A significant colony count from the catheter tip culture strongly supports the catheter as the source of infection.

Peripheral blood cultures can show bacteremia but don’t prove the catheter caused it. Urine culture and wound culture point to infections at those sites, not the catheter. Therefore, sending the catheter tip for culture provides the most specific evidence that the infection originated from the catheter.