Which test parameter is used to monitor unfractionated heparin therapy?

Which test parameter is used to monitor unfractionated heparin therapy?

• A. Platelet count
• B. Creatinine clearance
• C. Blood glucose
• D. Activated partial thromboplastin time

Answer: (B)

Activated partial thromboplastin time (aPTT) is the test used to monitor unfractionated heparin therapy. Heparin slows clot formation by enhancing antithrombin III, so measuring how long it takes blood to clot after platelet and contact activation reflects how strongly the blood is anticoagulated. The goal is a target aPTT value—often about 1.5 to 2.5 times the lab’s normal range—adjusted to the protocol, balancing effectiveness with bleeding risk. After starting or changing the infusion, aPTT is checked every 4–6 hours until the therapeutic range is reached, then monitored per protocol. Platelet count helps detect heparin-induced thrombocytopenia (HIT) but doesn’t measure heparin effect. Creatinine clearance and blood glucose don’t assess anticoagulation. In some settings, anti-Xa levels may be used as an alternative in special circumstances, but aPTT remains the standard monitoring test for unfractionated heparin.

Activated partial thromboplastin time (aPTT) is the test used to monitor unfractionated heparin therapy. Heparin slows clot formation by enhancing antithrombin III, so measuring how long it takes blood to clot after platelet and contact activation reflects how strongly the blood is anticoagulated. The goal is a target aPTT value—often about 1.5 to 2.5 times the lab’s normal range—adjusted to the protocol, balancing effectiveness with bleeding risk. After starting or changing the infusion, aPTT is checked every 4–6 hours until the therapeutic range is reached, then monitored per protocol. Platelet count helps detect heparin-induced thrombocytopenia (HIT) but doesn’t measure heparin effect. Creatinine clearance and blood glucose don’t assess anticoagulation. In some settings, anti-Xa levels may be used as an alternative in special circumstances, but aPTT remains the standard monitoring test for unfractionated heparin.