What is the purpose of monitoring PTT with unfractionated heparin therapy?

• A. To assess liver function.
• B. To ensure therapeutic anticoagulation and avoid bleeding.
• C. To monitor kidney function.
• D. To measure platelet counts.

Answer: (B)

Monitoring PTT during unfractionated heparin therapy is about gauging the drug’s anticoagulant effect so you can keep it in a safe, therapeutic range. Heparin boosts antithrombin III to inhibit thrombin and factor Xa, but individual responses vary, so a lab test is needed to estimate real-time anticoagulation. The PTT increases as heparin takes effect, and clinicians adjust the infusion to hit a target range that balances preventing clots with minimizing bleeding. This test isn’t used to assess liver or kidney function or platelet counts. Those aspects are checked by other labs, while PTT specifically reflects the anticoagulant activity of unfractionated heparin.