The correct method to obtain a sterile urine sample from an indwelling catheter includes:

• A. Clamping the catheter briefly, cleaning the rubber port with an alcohol wipe, and using a sterile syringe and needle to withdraw the urine
• B. Disconnecting the catheter and drawing from the drainage bag
• C. Drawing from the urethral meatus with a non-sterile syringe
• D. Collecting from the external surface of the catheter

Answer: (A)

The main concept is obtaining a truly sterile urine specimen from an indwelling catheter by accessing the urine through the catheter’s sampling port using sterile technique while keeping the system intact. Clamping briefly helps ensure the urine that is drawn reflects bladder urine rather than urine from the drainage bag, creating a small window of time where the urine in the sampling port comes from the bladder. Cleaning the rubber port with an alcohol wipe reduces surface contaminants, and using a sterile syringe and needle to withdraw the urine from the port preserves sterility and prevents introducing organisms from non-sterile sources. After obtaining the sample, the clamp is released so drainage can resume normally.

This approach avoids contaminating the specimen with contents from the drainage bag, the urethral meatus, or the catheter’s external surface, which would compromise the culture results. Drawing from the drainage bag or from the urethral meatus with a non-sterile syringe, or collecting from the catheter’s external surface, would introduce contamination and yield an inaccurate result.