Category: Phlebotomy

According to the World Health Organization, collecting blood samples from an existing peripheral venous access site can lead to false laboratory results due to hemolysis, contamination, and dilution by intravenous fluids. This is precisely why is not drawing above the IV site ok, as it creates a direct risk of mixing the infused solution with the blood specimen. Proper technique is critical for ensuring diagnostic accuracy and patient safety.

Heparin is a critical anticoagulant used in phlebotomy, with green-top blood collection tubes containing either its sodium or lithium salt to keep blood from clotting. Understanding **how does heparin prevent blood from clotting by phlebotomy** is key to appreciating its role in producing accurate laboratory test results for plasma chemistry.