For a prothrombin specimen collection from a patient with IVs in both arms, where is the best place to collect the specimen?

In the scenario of collecting a prothrombin specimen from a patient with intravenous (IV) lines in both arms, the best option is to collect the specimen from a different site entirely.

When a patient has IVs, blood drawn from the same arm as the IV may be contaminated with fluids or medications being administered through the IV line. This contamination can lead to inaccurate results, particularly for tests like prothrombin time, which is sensitive to anticoagulant therapy.

Collecting from above the IV (the first option) could still result in contamination, as the blood drawn could mix with the IV solution. Collecting from the wrist (the second option) could also pose similar issues, depending on the anatomy and proximity to the infusion site. Collecting below the IV (the third option) is not advisable as well, because it would inherently be exposed to the substances being infused, again risking contamination.

The best practice in this scenario is to choose an entirely different site for blood collection, such as the opposite arm, or perhaps a venipuncture site in a separate location. This ensures that the specimen is not influenced by the IV medications and provides a more accurate representation of the patient's coagulation status.