Paired blood cultures, drawn from the catheter and a peripheral vein, used for calculation of the differential time to positivity (DTP), have been proposed for the detection of catheter-related bloodstream infections (CRBSIs). The most relevant catheter lumen to be sampled in multi-lumen central venous catheters (CVCs) has not been recommended.
Forty-four febrile neutropaenic patients, following haematopoietic stem cell transplantation (HSCT) and with multi-lumen CVCs in place, were investigated using the DTP method of blood samples drawn from every lumen of the CVC and a peripheral vein.
Twelve of 44 patients (27 %) had CRBSIs, as determined by the DTP method. In 10 of 12 (83 %) febrile neutropaenic patients, after HSCT, CRBSIs originated from the CVC lumen used for parenteral nutrition and blood products only. 17 % had CRBSI originating from the other CVC lumen (p = 0.039).
In most patients, CRBSIs originated from the CVC lumen used for parenteral nutrition and blood products, indicating that this lumen is the main source of CRBSI. However, since 17 % of patients had CRBSIs originating from another lumen, each lumen of multi-lumen CVCs has to be considered as a potential source of CRBSI and should, ideally, be sampled in order to avoid failure in diagnostic procedures.