Why can't blood be drawn from the right upper extremity if there is a Hickman (central venous catheter) line on the right side of the body?

From the Guidelines

Blood should not be drawn from the right upper extremity if a Hickman catheter (central venous catheter) is present on the right side of the body due to the risk of contamination and inaccurate test results. When a central line is inserted, it creates a direct pathway to the central venous circulation, typically entering through the subclavian or internal jugular vein on the same side. Drawing blood from the arm on the same side as the catheter can lead to cross-contamination between the catheter and the peripheral blood sample. Additionally, medications or fluids being administered through the central line may be detected in the peripheral blood sample from that side, potentially causing falsely elevated medication levels or diluted laboratory values. This contamination occurs because the infusate from the central line can reflux into the venous circulation of the same extremity. For accurate laboratory results, blood should instead be drawn from the opposite arm or from a different site altogether. If peripheral access is limited, blood can be drawn directly from the central line using proper technique, including discarding an adequate amount of initial blood to avoid contamination with infusion fluids 1.

Some key points to consider when managing central venous catheters include:

• The type of catheter used, with silicone and polyurethane catheters being less thrombogenic than polyethylene or PVC ones 1
• The placement of the catheter, with the tip ideally positioned in the caudal superior vena cava (SVC) to minimize the risk of thrombosis 1
• The use of ultrasound-guided placement to minimize endothelial damage and reduce the risk of catheter-associated thrombosis 1
• Regular flushing of the catheter ports to maintain patency and reduce the risk of thrombosis and infection 1

It is essential to follow proper techniques and guidelines when managing central venous catheters to minimize the risk of complications and ensure accurate laboratory results.

From the Research

Drawing Blood from the Right Upper Extremity with a Hickman Line

• Drawing blood from the right upper extremity is not recommended if there is a Hickman line (central venous catheter) on the right side of the body due to the risk of contamination and inaccurate laboratory results 2, 3, 4.
• The presence of a central venous catheter, such as a Hickman line, can increase the risk of central-line associated bloodstream infection (CLA-BSI) if blood is drawn from the same extremity 5.
• Studies have shown that blood samples drawn from a central venous catheter can have different coagulation test results compared to samples drawn from peripheral veins, even when guidelines are followed 2.
• Additionally, infusions through a peripheral catheter can alter laboratory results, and it is recommended to avoid drawing blood from the same extremity as the catheter to prevent contamination and ensure accurate results 3.

Risk of Contamination and Inaccurate Results

• The risk of contamination and inaccurate results is higher when drawing blood from an extremity with a central venous catheter, such as a Hickman line 4.
• Central venous catheters can be a source of infection, and drawing blood from the same extremity can increase the risk of introducing bacteria into the bloodstream 6, 5.
• It is essential to follow strict guidelines and protocols for catheter insertion, care, and maintenance to minimize the risk of infection and ensure accurate laboratory results 6.