For example, a recall interval between 2 and 4 weeks might be reasonable following a VKA dose adjustment for an INR of 3.3 in a patient with generally stable INR control, whereas a recall interval not exceeding a few days might be needed after temporary interruption of VKA following an INR of 8.2 in a patient who recently started taking antibiotics. The panel identified the following additional research questions. (1) Does a strategy of using 1-week recall intervals for INRs that are farther out of range (eg, .4.0 or ,1.5) and 2- to 3-week recall intervals following INRs that are only slightly out of range (eg, 3.1-4.0 or 1.5-1.9) reduce the risk of mortality, recurrent VTE, and bleeding? (2) Could pharmacogenomic testing inform INR recall intervals by helping to predict the time required for a given patient to reach a new steady state following VKA dose adjustments? Question: For patients receiving maintenance VKA therapy for treatment of VTE should a longer (eg, 6-12 weeks) INR recall interval vs a shorter (eg, 4 weeks) INR recall interval be used during periods of stable INR control? For patients receiving maintenance VKA therapy for treatment of VTE, the ASH guideline panel suggests using a longer (6-12 weeks) INR recall interval rather than a shorter (4 weeks) INR recall interval during periods of stable INR control (conditional recommendation based on very low certainty in the evidence about effects ). Summary of the evidence. We found no systematic reviews that addressed this question. All studies included patients receiving VKA anticoagulation therapy but were not limited to patients being treated for VTE. The 2 RCTs directly compared outcomes between 4-week INR recall intervals and 6-week79 recall intervals for patients meeting predefined criteria for stable VKA anticoagulation. 