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HealthInfo Waitaha Canterbury

Warfarin monitoring

Aroturukitanga warfarin

If you're taking warfarin, it's 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's 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'll have an INR target range (usually between two and three) depending on the condition you're being treated for.

Your general practice team may do your INR tests or they may send you to a blood collection centre.

Some community pharmacies can also provide INR monitoring using a finger-prick test. Talk to your pharmacist and general practice team about this. This interactive map will show you if there is a pharmacy in your area that offers the service.

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

Written by HealthInfo clinical advisers. Last reviewed February 2023.


See also:

Food choices & warfarin

Page reference: 67663

Review key: HIBTM-167196