FAQs About Warfarin

What is warfarin? What conditions does it treat?

Warfarin is an anticoagulant and is used to prevent blood clots from forming or growing larger in your blood and blood vessels. Often referred to by the misnomer “blood thinner,” anticoagulants, such as warfarin (or brand of warfarin such as Coumadin®), help to prevent clots from forming in the blood by decreasing the clotting ability of the blood.

Anticoagulants are prescribed for those at increased risk of developing harmful blood clots, including people with irregular heartbeat, a mechanical heart valve, or those with disorders of the clotting system itself. Your doctor may have also prescribed warfarin if you have experienced a stroke, heart attack, a clot that traveled to the lung, or a clot in the leg. People taking warfarin will need to test their blood on a regular schedule.

Click here to learn more about how Acelis Connected Health can help you test your blood from the privacy of your own home.   


What are warfarin’s side effects?

Most people on warfarin notice they bruise easier than before they started the medication, or it takes longer for their blood to clot if they get cuts. Others experience nose bleeds or small amounts of blood in their urine or stool. Even though these are more common, you should tell your doctor.

Contact your physician if you experience any of the following:

· Severe or prolonged nose bleeds

· Red, dark yellow or cloudy urine

· Bloody or black, tarry stool

· Bruising with no cause, meaning you did not hit that part of your body on  anything, you didn’t fall, no trauma has occurred

· Prolonged bleeding from minor cuts

· Severe or heavier than normal periods

· Bloody or coffee-ground like vomit

· Coughing up blood

·  Persistent, severe headaches, backaches (especially upper-mid backache) or stomach pain.

All of these could be a sign or symptom of internal bleeding so immediate medical attention is very important.

What are INR levels and how often should I test them?

INR stands for International Normalized Ratio and it is a standardized number that measures the amount of time it takes for your blood to clot. People taking anti-clotting medicines or anticoagulants need to test their blood regularly to ensure their INR remains within the range deemed best for them by their physician. The “best” testing frequency is the one your doctor prescribed for you, which is optimized to ensure your INR stays in the target range.  The closer you keep your test results in your target range the safer you will be, and the better warfarin will work to protect you from developing a blood clot.

The STABLE (Self-Testing Analysis, Based 'on Long-term Experience) study, was the largest review of warfarin patient self-testing ever done. The STABLE Study studied 29,000 who test their own INR to see if increasing testing frequency for a person on warfarin could help reduce the risk of dangerous test results (critical values). The study showed weekly testing reduced risk by 46% over people who tested their blood twice a month. Weekly testing was close to 74% better at keeping their INR blood test close to their target range than people who tested their INR monthly.1,2,3

Weekly testing may not be easy or affordable if you have your blood drawn at a lab or your doctor’s office. People who test their INR at home often test weekly, eliminating travel to and from their lab. Monitoring your INR at home requires a prescription and the support of your doctor. Home INR Monitoring is covered by Medicare and most private insurance companies up to and including weekly testing.


Click here to learn more about Acelis Connected Health's home INR monitoring service.   

How should I take warfarin?

You should take warfarin EXACTLY as your doctor prescribes it to you. Most doctors ask people to take their warfarin at the same time every day, preferably in the evening. While you are on warfarin, it will be necessary to check your blood to see if the medication is doing its job and remains within your predetermined limit. Checking your blood will either require a blood draw or a fingerstick to check your INR, a measurement that shows the time it takes for your blood to clot. The test is performed at regular intervals as your doctor determines. Acelis Connected Health is the premier way to test your INR levels from the comfort of your own home.

Click here to learn more about the benefits of Acelis Connected Health.    

How can I travel and still not miss a test?

Your INR meter is designed to be portable and packable, no matter where you go. Whether you are traveling for the day or a month, you’ll never have to miss a test or try to find a local lab when you are part of Acelis Connected Health's premier home testing service. Acelis Connected Health’s services are perfect for snowbirds who travel seasonally because the service goes with you no matter where you stay or for how long.

Read more about traveling while taking warfarin.   

Why is testing my INR important?

The INR (International Normalized Ratio) is a blood test measuring how long it takes for your blood to clot.  It tells your doctor or nurse if your warfarin dose needs adjusting or if it is at the correct level for you. Warfarin is safest and most effective when your INR is within your prescribed target range, so it is important to check your INR per your doctor’s instructions/prescription.  Being in-range one or two times in a row doesn’t mean your next test will be in your target range because many things, including the foods you eat and the medication you take, can affect warfarin’s effectiveness. The only way to know if you are in range is by performing an INR test. Keeping the right amount of warfarin in your blood stream will reduce your risk of having a stroke or heart attack and also your risk of bruising or bleeding.1

Learn more about understanding your test results.   

FAQs about Acelis Connected Health

How does Acelis Connected Health’s service work?

Acelis Connected Health allows you to accurately and easily check your INR levels from wherever you are, giving you the freedom to travel, to relax, and to get back to living your life. From providing the medical-grade INR meter and testing supplies delivered right to your door, to sending a qualified trainer right to your home or doctor’s office, to delivering test results directly to your doctor, to reminding you if you miss reporting a blood test, Acelis Connected Health is the guardian angel of INR self-testing.

Click here to learn more about how Acelis Connected Health works.   

What kind of training is provided by Acelis Connected Health?

Acelis Connected Health believes that proper training is the key to home INR monitoring success. Because of this, we are the premier national service provider for self-testing and the only one that offers our personalized Face-2-Face® training for all customers on all INR systems. Our goal is to always ensure your success and confidence in testing your INR at home. Following your Face-2-Face training session, our Customer Outreach Program is available 7 days a week to answer questions about the testing process, provide trouble shooting for the testing meter or may need testing assistance.

Click here to learn more about the training process.   

Where and how do I record my testing results?

Reporting your results is easy! We offer multiple options to report your results, including a mobile app, a link from this web portal, and the telephone.

Learn more about how to submit your results here.   

Why is home testing better than testing at a lab?

Several recent studies have demonstrated that home INR testing leads to better care for people on warfarin. In 2011, the results of 22 such studies that included more than 8,000 people found that people testing their INR remotely had a 42% lower risk of new blood clots, a 12% lower risk of major bleeding, and a 26% lower risk of death.2


Some studies have also shown that INR results from point-of-care (the device your doctor may use to test your INR) devices such as the meter provided by Acelis Connected Health  are more reliable than results from a traditional lab, with the customer’s consistent use of the same meter and test strips cited as a key reason for the improved results. 1


Learn more about the benefits of Acelis Connected   

Additional FAQs

Why do you need to know private information such as my birth date or my doctor’s name?

Acelis Connected Health works hard to make testing your INR at home convenient for you every step of the way. We use the information you provide to determine your insurance eligibility so that we can provide accurate pricing, and we work directly with your doctor to obtain a prescription for Acelis Connected Health’s service. Once you are signed up and testing on your own, we use your doctor’s information to ensure your doctor receives your test results promptly after you test your INR at home. Acelis Connected Health reports your results according to your physician’s instructions. Your doctor will be in touch with you if a change to your medication is needed.

Learn more about how we work with your doctor.   

As with all the information we request, your privacy is a top priority.

Click here to find out more about privacy policy.   

I’m having trouble testing, what should I do?

Acelis Conneceted Health’s concierge service is here to help you with any questions or problems that arise from the test at home process. From questions about how your meter works, to problems with the fingerstick process, to queries about how to post results, our concierge team is experienced at getting you the information you need and the service you deserve.

Learn more about our Customer Support Program.   

Where does the meter come from? How do I get supplies for testing?

Acelis Connected Health will provide you with your meter and your first delivery of testing materials at the time of your Face-2-Face training session. Many insurance plans, including Medicare, provide testing supplies for individuals who have been trained and demonstrated the correct use of the device.

Learn more about insurance coverage.   

Will taking a new medication or supplement affect my INR?

While taking warfarin it is important to let your doctor know all prescription and over-the-counter medications you take, including pain relievers, cold medicines, and herbal supplements.  


Click here to learn more about drug interactions   


Do I need to watch my diet when taking warfarin?

Understanding how diet can affect your INR is an important aspect of living a healthy life while on warfarin. Although there is no specific "warfarin diet,” it is important to pay attention to what you eat while taking warfarin as some foods and beverages can alter the effectiveness of warfarin.

The most important thing to remember is to remain consistent with your diet. Consistency in diet means to be aware of the type of foods you choose every day, pay attention to your portion sizes and be aware of the frequency you consume foods high in Vitamin K. The Acelis Connected Health website has made it easy for you to find the levels of Vitamin K in your food. We have assembled more than 5,000 choices of foods and beverages for your reference in our Vitamin K Guide. 

Consistency in diet also allows you variety and choices in life, enabling you to keep your INR test results in range more often. As always, talk to your doctor about any changes to your diet, medication or supplements.

Click here to access our Vitamin K Guide.   

What happens if I forget to test or don’t report my results?

We will remind you! If you or your loved one doesn’t report their test results according to the testing schedule prescribed by the doctor, our Testing Services team will reach out to remind them.

Learn more.   


  1. 1. Ansell, J. March 2012. Patient Self-Testing: Real-World Experience Within a Comprehensive Support Service Represents a New Standard of Care, Attaining High Quality Anticoagulation Control.Poster presented at: American College of Cardiology.
  2. 2. Center for Medicare and Medicaid Services. Decision Memo for Prothrombin Time (INR) Monitor for Home Anticoagulation Management  (CAG-00087R) [Memorandum]. Baltimore, MD. 2008.
  3. 3. Hylek, E., et al. An Analysis of the Lowest Effective Intensity of Prophylactic Anticoagulation for Patients with Nonrheumatic Atrial Fibrillation. NEJM, Vol.335, No.8, p.540-6. 1996.














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