Anticoagulation Calculator

This calculator suggests a warfarin dose adjustment, recheck interval, and bleeding-risk category from a current INR compared against a target range (rather than a single target value), using a simplified empiric percentage-based nomogram similar in style to common hospital dosing protocols. Below the target range, the suggested increase grows with how far below and how low the absolute INR is (5% for a small gap, 10% for a larger gap, 15% once INR is both below the target's low bound and under 1.5). Note that the 15% step only ever applies to an INR that is ALSO below the target's low bound: if a clinician sets a lower target-low bound, such as 1.0, an INR between that bound and 1.5 is not automatically boosted to the 15% step -- it may instead read as in-range with no adjustment suggested at all. Above the target range, the suggested decrease similarly grows with severity, culminating in a full hold (-100%, reducing the suggested dose to zero) for any INR over 5.0 -- this calculator does not distinguish a brief hold from stopping therapy entirely, and does not add vitamin K guidance, which real supratherapeutic-INR protocols often include at higher INR levels or with bleeding.

Within the target range, no adjustment is suggested and the recheck interval extends to monthly, reflecting a stable result. The bleeding risk category is a simplified banding of the absolute INR level alone (low up to 3.0, moderate 3-4, high 4-5, critical above 5), independent of the patient's target range, indication, or other bleeding risk factors such as age, prior bleeding, or interacting medications -- none of which this calculator collects. Current weekly dose only scales the suggested new dose; it never changes which percentage band, recheck interval, or bleeding-risk category applies. This is a decision-support estimate, not a substitute for individualized anticoagulation management.