Low molecular weight heparin (LMWH) dosage is based on which criterion?

Low molecular weight heparin (LMWH) dosage is primarily based on the patient's body weight. This approach ensures that the anticoagulant effect is appropriately calibrated to the individual's size and metabolic rate, as larger individuals generally require higher doses to achieve the desired therapeutic effect. The weight-based dosing regimen helps to optimize the efficacy and safety of LMWH, reducing the risk of under-anticoagulation or over-anticoagulation.

Other criteria such as INR, PT, and PTT are useful for monitoring and managing other types of anticoagulation therapies, primarily those related to vitamin K antagonists like warfarin or unfractionated heparin. However, these tests are not standard indicators for adjusting LMWH dosages, which is specifically tailored to the patient’s weight. Hence, using weight as a criterion for LMWH dosing is the best approach to ensure therapeutic effectiveness while minimizing potential side effects.