International Normalised Ratio (INR)
What is it?
When you take Warfarin, you need regular blood tests called the international normalised ratio (INR). It measures how long it takes your blood to clot. The longer your blood takes to clot, the higher the INR.
Most people taking anticoagulants have a ratio of between 2 and 3.5. This means their blood takes 2 to 3.5 times longer to clot than usual.
The dose of warfarin you need depends on your blood test result. If the blood test result has gone up or down, your warfarin dose will be increased or decreased.
You'll have a test every 1 or 2 days when you first start taking Warfarin, then once or twice a week, until your ratio is stable at the target level.
Once your blood test results are stable, you might only need a blood test up to once every 12 weeks. You might need blood tests more often than normal if you start other new medicines, or when you are ill.
DO BOOK IF:
✓ You are taking Warfarin and are due your next INR test. This needs to be as close to your INR due date as possible.
DO NOT BOOK IF:
⊘ You do not take Warfarin medication.
⊘ You need a regular blood test. Please book a 'Blood Test Only As Requested By GP' appointment instead.
⊘ This will be your first INR appointment after starting Warfarin. This requires a longer appointment so please call us on 01539 718080 option 1 to book this. After your first appointment, you will be able to book this INR slot going forward.
