Heparin Weight-Based Nomogram

About this calculator

The weight-based heparin nomogram sets an initial IV bolus (commonly around 80 units/kg) and starting infusion rate (commonly around 18 units/kg/hr) from the patient's weight, then adjusts the infusion rate up or down in defined steps based on where the measured aPTT falls relative to the target therapeutic range — too low means increase the rate and possibly re-bolus, too high means decrease or hold the infusion.

ICU and hospital-floor nurses and physicians use this protocol to keep patients on unfractionated heparin — for conditions like DVT, pulmonary embolism, or acute coronary syndrome — safely anticoagulated, since heparin's effect varies widely between patients and needs frequent aPTT-guided titration rather than a single fixed dose.