Critical Care Trauma Centre


"Catheter Associated Bactermemia" (CAB) assessment is a blood culture test that is performed to determine whether an existing intravascular device is the likely source of a blood stream infection. To order a CAB assessment, draw blood cultures from the line(s) and from a peripheral sample. Draw them within 15 minutes of each other. In the comments section, request "CAB". The lab will only perform a CAB assessment if a peripheral sample has been obtained with the line culture. The lab will then report the time that each sample becomes positive (called "time to positivity").

If both samples become positive with the same organism within a two hour period of time, the patient is identified as having a bactermia. If the line becomes positive > 2 hours before the peripheral culture, the patient is diagnosed with a Catheter Associated Bacteremia.

CAB assessments should only be ordered if the patient has a previously established intravascular line. CAB assessment is not indicated if all intravascular devices are newly established.

CAB assessment is not indicated if removal of the intravascular device is planned. Instead of a CAB assessment, send blood from the line PLUS the catheter tip for culture. If the blood culture is positive and the tip has a colony count > 15, CAB has been identified. A CAB assessment may still be ordered to assess one of the remaining lines that are not being removed.



Brenda Morgan
Clinical Nurse Specialist, CCTC
Last Update: April 19, 2007