Partial Thromboplastin Time: Accurate Measurement Through Evidence-Based Practice.

At the University of Pittsburgh Medical Center's Hillman Cancer Center, multiple occurrences of critically elevated partial thromboplastin time (PTT) levels drawn by central venous access devices (implantable ports) were determined to be inaccurate. Root cause analysis revealed the institutional policy and staff education for collection did not support peripheral venipuncture for coagulation panels. Peer-reviewed literature and case studies were evaluated by the evidence-based practice council, and the data revealed that PTT levels yielded incorrect results when drawn through an implantable port. This suggested that peripheral venipuncture might be preferable.