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HealthInfo Canterbury

Warfarin monitoring

If you are taking warfarin, it is important that you have regular blood tests to get your dose of warfarin correct. If your dose is too high, you may have bleeding problems. If it is too low, it might not work.

The blood test checks how long it takes your blood to clot and is called an INR test. You will have an INR target range (usually 2 to 3) depending on the condition you are being treated for.

After each test, your GP will tell you what dose to take, and when to have your next test. You may need extra tests if you start on another medication or become unwell. Your GP or pharmacy can give you booklets and calendars to help you record and remember your blood tests and doses of warfarin.

Some community pharmacies can now provide INR monitoring using a finger-prick test. If you are interested in this service talk to your pharmacist and GP or practice nurse.

This interactive map will show you if there is a pharmacy in your area that offers the service.

Written by HealthInfo clinical advisers. Last reviewed May 2020.

See also:

Food choices & warfarin

Page reference: 67663

Review key: HIBTM-167196