Calculating TTR for patients that have monitoring intervals greater than 56 days and do not have 100% of INR results in range. The Stage 3 measure is designed to calculate TTR for each patient using one of two methods, depending on the interval (gap) between INRs and whether INRs are within range. However, there is a hypothetical subset of patients for whom a TTR cannot be calculated.

Currently, our only workaround is to provide detailed guidance as part of the measure specification for MUCD-19 (ADE Prevention and Monitoring: Warfarin Time in Therapeutic Range (TTR)).