← Back to All Calculators
Heparin Infusion Protocol (UFH)
Weight-based unfractionated heparin dosing with aPTT adjustment
Patient & Indication
Required (20–300)
—
Bolus (units)
—
Bolus (mL) @100 U/mL
—
Infusion (units/hr)
—
Infusion (mL/hr) @100 U/mL
aPTT Adjustment Table (target 50–70 sec)
| aPTT (sec) | Rebolus | Rate Change | Hold |
|---|---|---|---|
| < 35 | 80 U/kg | Increase by 4 U/kg/hr | None |
| 35–49 | 40 U/kg | Increase by 2 U/kg/hr | None |
| 50–70 | None | No change (therapeutic) | None |
| 71–90 | None | Decrease by 1 U/kg/hr | None |
| 91–120 | None | Decrease by 2 U/kg/hr | 30 min |
| > 120 | None | Decrease by 3 U/kg/hr | 60 min |
Standard concentration: 25,000 units in 250 mL NS = 100 units/mL. Check aPTT 6 hours after initiation or any rate change. Monitor platelets every 2 days for HIT. For STEMI/PCI, use ACT-guided protocol-specific dosing.
