Quality & Safety

Partial Thromboplastin Time: Accurate Measurement Through Evidence-Based Practice

Summer Drummond

Gloria Gotskie

Darlene Landi

Janet Lindberg

Kate Ross

Susan Siak

Mary Reslink

Christine Chubeck

Rebecca Brown

Leah Agostino

partial thromboplastin time, implantable port, coagulation panel, venipuncture, blood draw
CJON 2019, 23(4), 431-433. DOI: 10.1188/19.CJON.431-433

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.


  • PTT blood draws from implantable ports may result in falsely elevated levels.
  • Oncology nurses might consider peripheral venipuncture for coagulation panel collection, even for patients with implantable ports.
  • To ensure best safety practices related to PTT draws, quality and safety leadership can review institutional policies and nursing education.
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