Time in Therapeutic Range Calculator (TTR)

The Time in Therapeutic Range Calculator (TTR) assesses the mean therapeutic INR range for patients who have sufficient INR values. It provides vital information about whether the patient is benefiting from taking Warfarin.

The calculator scans the patient's record for INR values, ignoring the first 6 weeks of results after Warfarin indication setting the start date to the first INR after that date and the end date to the last INR after that date. A warning occurs if the patient does not have a minimum of 6 months results but a calculation will still be completed. It then uses the therapeutic range which defaults to the range saved against the patient (usually 2-3), to calculate the percentage assuming that changes between consecutive INR measurements are linear over time.

Accessing the Time in Therapeutic Range Calculator

1. From Consultation Manager, select Vision+ from the floating toolbar and select Calculators - Other - TTR.

   

   Note - You can also access the TTR calculator from the Anticoagulation Manager template if you have purchased the Anticoagulation Manager module.
2. The Time in Therapeutic Range Calculatordisplays:

   

3. From the calculator screen you can amend any of the boxes apart from the actual Time in Therapeutic Range calculation. The options are:
   • Start Date - Ignores the first 6 weeks of results after Warfarin indication, then sets the start date to the first INR after that date.
   • Date - Latest INR value.
   • Target - Patient's target INR.
   • INR - All INR values listed.
   • Time in Therapeutic Range - Calculation which assesses the mean therapeutic INR range for the patient.
   • Clinical term - The Clinical term, Score and Event Date record in the patient's recorded.
4. Select OK to save the result to the patient's record or OK & Attach to also save the questionnaire.
5. The appropriate clinical term saves to the patient's record.
6. The start and end date display in the notes box for reference purposes:

   

TTR Reports

From Vision+ Practice Reports you can view TTR reporting cohorts.