Home INR (International Normalized Ratio) Test

Home INR (International Normalized Ratio) Test

 

About the INR test

The home INR test measures your blood clotting time using a small device called a home INR meter. You can do the test quickly at any time, rather than having to go to a lab.

You need to measure your INR to be sure you are taking the right dose of warfarin, also known by the brand names Coumadin or Jantoven. Warfarin is a blood thinner to prevent blood clots. It slows the amount of time it takes for your blood to clot. This can cause bleeding problems so regular testing is needed to keep you safe.

Your health care team will set your goal range for your INR level and your dose of warfarin. Your dose may be changed to help keep your INR in your range. Keeping your INR in your range is key to safely taking warfarin and not having problems with bleeding or clotting.

 

Read your home INR meter manual

You will be taught how to use your meter, report your results and order supplies.

Read the instructions that come with your meter. Feel free to contact the company if you have specific questions about how to use your meter.

The instructions given here may vary slightly from your meter instructions. Be sure to follow the steps for your meter to get the most accurate test results.

 

My INR range

My goal range for my INR is between __________________ .

I am to do my home INR test on ____________________________ or as directed.

 

Gather your supplies

To test your INR, you will need these supplies:

  • Home INR meter
  • Test strip - these are specific to your model of meter. Be sure to check the expiration date on the test strips. Do not use expired test strips. Also check that the test strip code and the code chip in the meter match.
  • Lancet - a short needle to prick your skin to get a blood drop
  • Lancing device - holder for the lancet to control how deeply the needle goes into your skin
  • Clean cotton balls or gauze pads - used to stop bleeding after the test
  • Needle disposal container - use a heavy plastic container with a screw on lid or buy a container at the drug store.

 

Steps to do the test

Wash your hands well with warm water and soap and then dry with a clean towel.

Set up your lancing device.

  • Remove the cap from the lancing device. Put a lancet or needle into the lancing device and twist off the cap so the needle is seen.
  • Put the cap back on the lancet, being careful not to touch the needle. Set it down until you are ready to use it. 

Prepare your meter for use.

  • Get a test strip out of the bottle and replace the lid to keep moisture away from the other strips. Be sure your strip code matches the code chip on your meter.
  • Turn your meter on. Place the test strip into the meter or have it ready to put the blood on it as instructed for your meter.

Get your blood sample.

  • Pick up the lancing device and place it against the side of your finger and hit the button to poke the needle into your finger. Set the lancing device down.
  • Place a drop of your blood on the test strip.
  • Start the test as directed by your meter, or it may start to run on its own. You will get a result in a minute or less.
  • Hold a clean cotton ball or gauze pad with even pressure to the finger stick site to stop the bleeding. Note the INR reading on your meter.

Clean up and store your meter for next use.

  • Remove the test strip from the meter and throw it  and the cotton ball or gauze in the trash.
  • Turn off the meter if it does not turn off by itself.
  • Remove the needle from the lancing device and toss it into a needle disposal container.
  • Wipe your meter off as directed by the manufacturer, if needed and return it to its case. Put the supplies away and out of the reach of children or pets until needed for your next test.
  • Wash your hands well with soap and water and dry with a clean towel.

Report your INR right away to your doctor or other office as directed. Based on your meter, you may report your results using an app on your phone or calling the home monitor company. Some meters may send your results automatically.

You will be contacted if you need to adjust your warfarin dose.

 

Tips to get a good blood drop

  • Wash your hands in warm water so your fingers warm up to increase blood flow.
  • You can also warm your fingers by holding your hands under your armpit or massaging the hand.
  • Do not squeeze or milk the end of your finger.
  • Be sure your finger is dry before doing the stick so the water does not dilute your blood.
  • If you are not able to get enough blood, try another part of the finger or a different finger.

Talk to your doctor or others on your care team if you are having problems getting a good blood drop.


Regular lab tests

You may need to have a prothrombin (PT) time test done in the lab from time to time to check the accuracy of your home meter results.

 

For more information

You may have been given other handouts to give you more information, or ask your care team to get you a copy.

  • Warfarin
  • Diet and Warfarin
  • Blood Thinners: How to Prevent Bleeding

Talk to your doctor or others on your care team if you have other questions about your condition or your INR levels.

Contact the home INR meter company if you have specific questions or concerns about your home INR meter.

 

© 2021 – January 11, 2021. The Ohio State University Wexner Medical Center.

This handout is for informational purposes only. Talk with your doctor or healthcare team if you have any questions about your care. For more health information call the Library for Health Information at 614-293-3707 or email: health-info@osu.edu.