Table 1.

Extended INR testing policies by anticoagulation clinic

	Definition of “stable warfarin patient”	Maximal allowed INR testing interval
Clinic 1	12 weeks without maintenance dose change and no out of range INRs	10 weeks
Clinic 2	6 months without a weekly dose change and no INRs >10% above/below therapeutic range	12 weeks
Clinic 3	6 months without a weekly dose change and no INRs >10% above/below therapeutic range (both have to be met)	6 weeks
Clinic 4	10 weeks of no INRs > 10% above/below therapeutic range	6 weeks
Clinic 5	4 months without any INRs >10% out of range and no weekly dose change	6 weeks