Time in Therapeutic Range Calculator (TTR)

The Time in Therapeutic Range (TTR) measure (expressed as a percentage) 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.

How the TTR Calculator Works

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.

To access the Time in Therapeutic Range Calculator (TTR):

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

   

   Vision+ Calculators

   Note - You can also access the TTR calculator from the Anticoagulation Manager template if you have purchased the Anticoagulation Manager module.

2. Select TTR.

   

   Other - TTR

3. The TTR Calculator displays.

   

   TTR Calculator

4. 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
   • Read code - The code, Score and Event Date recorded in the patient's recorded
5. Click OK to record the score 42QE2 - INR percentage time in therapeutic range and the date, or OK & Attach to also record the questionnaire.
6. The code 42QE2 - INR percentage time in therapeutic range is recorded in the INR SDA along with score. The start and end date also recorded in the notes box for reference purposes.

   

   INR SDA

TTR Reports

From Vision+ Practice Reports you can view TTR reporting cohorts. For information on how to run the Anticoagulation Manager report - See Anticoagulation Manager Reports.