What is an INR Test?
An INR test (international normalized ratio) is a blood test that measures how long it takes for blood to clot.
Why is it done?
Your doctor might request an INR test to:
- Check for bleeding problems or disorders
- Check whether anti coagulation medicine is working
- Screen people having surgery for unrecognized bleeding problems
- Diagnose liver problems
How do I prepare?
No special preparation is needed for your INR test. You can eat normally and take your medications, at their usual times, before the test.
- Bring a list of your current medications and non-prescription medications (including herbal or dietary supplements)
What happens during the test?
An INR test is performed by a medical clinician.
- A single drop of blood is drawn by a finger prick.
- Results are shown in less than 30 seconds.
- Your clinician will determine whether your results are high, low or within the normal range.
- 0.5: Considered low, indicates a risk of developing a blood clot
- 2.0 - 4.0: The most common INR range for someone on anticoagulants
- 5.0: Considered high, indicates blood clots too slowly and there may be a risk of bleeding
Frequently Asked Questions
What is coagulation?
Coagulation is the formation of blood clots inside your body. Your body works to form a clot to help stop bleeding when you have a cut or injury.
What is my target INR level?
The ideal INR range will vary depending on a number factors including medical conditions, reason for taking anticoagulants, etc. Please consult your doctor regarding the appropriate range for you.
What can affect my INR levels?
There are many factors that can affect your INR levels including medications, supplements, certain foods and beverages and stress. Talk to your doctors for further information on how to control your levels.
What if my results are out of the range?
If your INR is high, your blood may not from clots quickly enough and you may be at an increased risk of bleeding. If your INR is low, you may be at risk of developing excessive blood clots. Talk to your doctor if your level is outside of your appropriate target range.
How/When do I get my INR test results?
Your INR results will be available within 30 seconds of your test. Your clinician will determine whether your results are within your target range.
How often should I test my INR levels?
INR test frequency should be determined by your doctor.