INR self-testing – why the need?

  • Many patients who attend the clinic continue to suffer from poor INR control, increasing their risk of a stroke
  • Many warfarin clinics are operating at near capacity and are near financial loss.
  • Regular clinic visits can be inconvenient and costly, having unnecessary implications on patient’s day to day lives.


Our clinical studies consistently show a marked reduction in adverse events for those on the INR self-testing service compared to those who are not. In a pilot of this service time in therapeutic range (TTR) increased on average by 20 percentage points.

Our solution

A digitally enabled INR self-testing care pathway which enables warfarin patients to monitor their health from the comfort and convenience of their own home

The Health Call INR self-testing service enables patients to self-test their international normalised ratio (INR) from their own homes, meaning they do not have to attend the warfarin clinic every few weeks.

The INR self-testing service provides patients with a Roche self-monitoring device. Patients then provide their care team with their readings using a method which suits them, either through an automated phone call or an on-line portal.

Any irregular readings or adverse answers alerts the warfarin clinic so contact can be made with the patient. The INR and warfarin data is directly sent to the patient’s clinic where, using anticoagulation software, the next warfarin dose and date of the next INR test is calculated. The patient then receives a second automated phone call at a pre-agreed time. If readings are normal, the automated phone calls continue. In the case of the online portal, email reminders continue as normal.

The Health Call INR self-testing service has transformed the lives of patients across the UK. So much so, we believe INR self-testing should be available to all patients on warfarin.

The benefits of INR self-testing

  • Improved clinical outcomes – We found over 70% of patients that moved to the NHS Health Call INR self-testing service improved their time in therapeutic range by 20% and our 24 month follow up showed that this change is long-lasting
  • Improved patient satisfaction – 100% of those on the Health Call INR self-testing service said they’d recommend the service to others
  • Cost savings – Our research concluded that INR self-testing was found to be 17% cheaper than clinics and 25% cheaper than home visits
  • Improved efficiency – An estimated 20-25% of warfarin users would benefit from INR self-testing, reducing out-patient appointments by over 20%*All data collated from a major study at County Durham & Darlington NHS Foundation Trust

INR Self-monitoring Service faqs

What is the Health Call INR Self-monitoring Service?

The NHS Health Call INR self-testing service is designed to help patients manage their INR from home, reducing the need to travel to the warfarin clinic. With our digital health technology, a patient can take their blood test at home and submit the readings weekly. If any readings are irregular, a clinician will get in contact immediately.

What is involved in the Health Call INR Self-Monitoring service?

You will receive full training on how to test your blood using the digital health self-monitoring devices. You will arrange with your clinician for an automated phone call or email on the same day and time each week. The phone call or email will ask you a few questions around your general health and well-being and will ask you to submit your reading. Your readings will be checked by the warfarin clinic nurse who will then decide your next dosage which will be communicated to you by another automated phone call or email..

When will the scheduled call or email take place?

You will need to be available for 2 calls or email. The first call will collect your blood results and the second one will ask you a few questions around your warfarin dosage. A convenient date and time will be arranged with your clinician.

Don’t worry if you miss the call. The call will retry you a further 3 times at half-hour intervals. An alert will be sent to the warfarin clinic if they are unable to make contact with you.

If you choose to receive an email rather than a phone call, you will need to respond to the first email between 5am and 12 midday. The return email with dosing instructions and the next test date can be accessed from 4pm to midnight on the same day.

To access the email service, you will be sent access documents via post. You will need your NHS number, Access Code, Username and Password each time you log onto the system.

What are the benefits of the INR Self-Monitoring Service?

The programme enables home testing which means you won’t have to travel to the hospital clinic. Your results will still be reviewed by your clinician and you will still be able to contact them via telephone. You will be able to take your device with you to work, or when you go on holiday just as long as you have a phone or email-capable device with you. The service is designed to make the lives of those on warfarin easier.


I live in Gainford [a village in a rural part of Durham] and it’s eight miles either way to Barnard Castle Hospital, or Darlington, or Bishop Auckland to get to a clinic... It's much easier for me (self-testing).

They don’t have to come to hospital every two weeks, they don’t have to pay £2.50 for parking for that hour and sit in queues in the clinic, they don’t have to ask for time off work, they can go on their holidays to Spain or go off caravanning and still receive their warfarin dose from the nurses at County Durham and Darlington Foundation Trust.

Being able to self-test has given me a greater sense of freedom. For me, the biggest benefit is that I can go on holiday safe in the knowledge I can still manage my INR levels.

A number of our patients tell us that, when they come to clinic, they have to take the time as holiday. Self-testing gives them the freedom to test at home.


Watch this ITV news clip to learn how Health Call is enabling Derek Jones to self-test his INR levels without having to attend the clinic. Download the INR self-testing product brochure and gain more understanding into the INR service.

INR Leaflet

INR Self-Testing Product Brochure

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