Which laboratory value monitors heparin therapy?

Which laboratory value monitors heparin therapy?

• A. Platelet count
• B. CBC
• C. INR
• D. PTT

Answer: (D)

Monitoring heparin therapy relies on the partial thromboplastin time. Heparin works by enhancing antithrombin III, which inhibits thrombin and factor Xa, slowing clot formation. The aPTT (PTT) measures the time it takes for plasma to clot via the intrinsic and common coagulation pathways, so it directly reflects the anticoagulant effect of heparin. The therapeutic goal is to keep the aPTT in a defined range (often 1.5–2.5 times the baseline or a lab-specified target) to prevent thrombosis without causing bleeding. If the aPTT is too long, you’d reduce or pause the infusion; if it’s too short, you’d increase the dose. Platelet count can indicate potential heparin-induced thrombocytopenia, but it doesn’t monitor heparin’s anticoagulant effect. INR monitors warfarin, not heparin, and a CBC is a broad panel, not specific to anticoagulation monitoring.

Monitoring heparin therapy relies on the partial thromboplastin time. Heparin works by enhancing antithrombin III, which inhibits thrombin and factor Xa, slowing clot formation. The aPTT (PTT) measures the time it takes for plasma to clot via the intrinsic and common coagulation pathways, so it directly reflects the anticoagulant effect of heparin. The therapeutic goal is to keep the aPTT in a defined range (often 1.5–2.5 times the baseline or a lab-specified target) to prevent thrombosis without causing bleeding. If the aPTT is too long, you’d reduce or pause the infusion; if it’s too short, you’d increase the dose. Platelet count can indicate potential heparin-induced thrombocytopenia, but it doesn’t monitor heparin’s anticoagulant effect. INR monitors warfarin, not heparin, and a CBC is a broad panel, not specific to anticoagulation monitoring.