What's this test for?

This test is ideal if you're taking Warfarin (a blood thinner) and need to monitor how well it's working, or if you're experiencing unexplained bruising, bleeding, or blood clots. It measures how quickly your blood clots, which helps your doctor adjust your medication dosage to keep you safe. Many people use this test regularly to ensure their blood isn't clotting too quickly (which increases stroke risk) or too slowly (which increases bleeding risk).

What happens after I get my results?

You'll receive detailed doctor notes in simple language explaining what your PT/INR levels mean for your bleeding and clotting risk. These notes include personalized guidance on whether your Warfarin dosage needs adjustment, dietary considerations (like vitamin K intake), and when to follow up with your prescribing doctor. You'll also get the standard lab report and can track your INR levels over time using our trends feature, which is especially helpful for managing anticoagulation therapy safely.

What's included in this test?

This test measures Prothrombin Time (PT) and International Normalized Ratio (INR). PT measures the time it takes for your blood to clot through the extrinsic clotting pathway, while INR standardizes this measurement so it can be compared consistently across different labs. Together, these measurements help monitor Warfarin therapy effectiveness and detect potential bleeding or clotting disorders.

How should I prepare for this test?

No fasting is needed for this test, making it convenient to schedule at any time of day. You can eat and drink normally before your blood draw. However, if you're taking Warfarin or other blood thinners, continue taking them as prescribed unless your doctor specifically instructs otherwise.

Who should consider getting this test?

This test is essential for anyone taking Warfarin or other anticoagulant medications to prevent blood clots, strokes, or heart attacks. It's also important for people with a history of blood clots, atrial fibrillation, heart valve replacement, or those being evaluated for unexplained bleeding or bruising. If you have a family history of clotting disorders or have experienced abnormal bleeding, this test can provide important insights.

What symptoms indicate I may need this test?

Consider this test if you experience frequent or unexplained bruising, nosebleeds that are hard to stop, bleeding gums, unusually heavy menstrual periods, or blood in your urine or stool. Other warning signs include prolonged bleeding from minor cuts, red or dark brown urine, or black tarry stools. If you're on blood thinners and notice any unusual bleeding or develop new blood clots, this test is crucial.

What is INR and why does it matter?

INR stands for International Normalized Ratio, and it's a standardized way to measure how long your blood takes to clot compared to normal. For most people not on blood thinners, INR is around 1.0, but if you're taking Warfarin, your doctor typically wants your INR between 2.0 and 3.0 to prevent dangerous blood clots. Keeping your INR in the right range is crucial because too high means bleeding risk, while too low means clotting risk.

What does a high INR mean?

A high INR means your blood is taking longer than desired to clot, which increases your risk of bleeding or bruising easily. If you're on Warfarin, this may mean your dose is too high and needs to be reduced. High INR can also be affected by certain foods high in vitamin K, other medications, alcohol consumption, or liver problems.

What does a low INR mean?

A low INR means your blood is clotting faster than desired, which may not provide adequate protection against dangerous blood clots if you're taking Warfarin. This could mean your medication dose is too low and may need to be increased. Low INR can be caused by not taking your medication consistently, eating too many vitamin K-rich foods, or certain medications that interfere with Warfarin.

How often should I retest my INR?

If you're newly starting Warfarin or your dose was recently changed, you'll typically need to test every few days to weekly until your INR stabilizes in the target range. Once stable, most people test monthly, though your doctor may recommend more or less frequent testing based on your individual situation. Consistent monitoring is essential for safe and effective anticoagulation therapy.

Getting your blood test with us is easy, private & backed by the power of science.Long story short: In the test options, use the filters or search box to narrow your choices and find the test you want. If you need a hand navigating through options, text our super friendly support team at 754-799-7833, and we'll provide tailored suggestions to help you find the ideal test. Once your order is placed, we’ll create your doctor’s lab order remotely, without any need for you to make a trip to a doctor in person or to talk to the doctor. Expect to receive your doctor’s lab order right in your inbox. It will also be in your patient portal if you need to find it later. We’ll also include instructions regarding fasting and other requirements for your test. Your patient portal will be auto-created hassle-free during checkout. If this is your first time ordering, you'll be prompted to create a password for instant login access to your patient portal. It's a quick way to conveniently access your orders and results whenever you want. When you’re ready, visit one of our 4,000 locations. Just bring your ID – no printing or faxing of your lab order is needed, as your order and details will already be in the lab system. Note that most lab locations don’t accept walk-ins, so it’s best to book an appointment in advance. Don’t worry – we’ll provide detailed instructions along the way. You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy! If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com and we'll gladly help you.

How do I know which test to get?

In the test options, find the test you want. If you’re not sure which test to get, we can lend a hand in finding the right option. Just text or call us at 754-799-7833, email us at support@privatemdlabs.com, and we'll gladly help you. We've got your back and reply quickly.

When will my lab results be available?

Most test results will be available within 1–3 business days. Once they're ready, we'll send an email and text message to let you know. After your blood draw, just hang tight and don't worry – we'll keep you updated and in the loop! If you have any further questions, please text us at 754-799-7833 or email support@privatemdlabs.com, and we'll gladly help you.

Is it possible to make changes to my lab order if I made a mistake with the name, date of birth, or any other details?

Absolutely! We totally understand that errors can happen. No worries, we're here to help you. Just reach out to us via text at 754-799-7833 or shoot us an email at support@privatemdlabs.com. Remember to include your order number and let us know the correct information you’d like to update. Our awesome team will jump right in and make sure everything is sorted out and accurate for you. There are no changes necessary if your address is wrong on the requisition though. We don’t mail anything out. Our lab requires an address to be listed to generate an order.

Do you accept health insurance?

Only HSA & FSA is accepted. Our services are strictly self-pay and cannot be submitted to your health insurance provider except for Health Savings Accounts or Flexible Savings Accounts. This policy applies to all insurance companies, including federal health insurance programs like Medicare. If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com.

Can I cancel my order?

Yes. We get it – sometimes your needs change. As long as your samples haven’t been collected yet, we’re happy to help you cancel your order. If you have any further questions, please text us at 754-799-7833 or email support@privatemdlabs.com. You can read more about our cancellation policy here.

How can I find a lab location near me?

During the ordering process, you’ll be able to select a specific lab near you, with no strings attached! You can switch it up later easily and visit any of our authorized locations as long as it’s the same lab company you selected your test for (Quest Diagnostics or Labcorp). Before you proceed with your order, feel free to browse through all our lab locations here. This will give you the peace of mind of knowing that there's a lab nearby your home, office or your favorite gym. If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com and we'll gladly help you.

PT/INR Test - Blood Clotting & Warfarin Monitoring

Getting your blood test with us is easy, private & backed by the power of science.

Long story short:

In the test options, use the filters or search box to narrow your choices and find the test you want.
If you need a hand navigating through options, text our super friendly support team at 754-799-7833, and we'll provide tailored suggestions to help you find the ideal test.
Once your order is placed, we’ll create your doctor’s lab order remotely, without any need for you to make a trip to a doctor in person or to talk to the doctor. Expect to receive your doctor’s lab order right in your inbox. It will also be in your patient portal if you need to find it later. We’ll also include instructions regarding fasting and other requirements for your test. Your patient portal will be auto-created hassle-free during checkout.
If this is your first time ordering, you'll be prompted to create a password for instant login access to your patient portal. It's a quick way to conveniently access your orders and results whenever you want.
When you’re ready, visit one of our 4,000 locations. Just bring your ID – no printing or faxing of your lab order is needed, as your order and details will already be in the lab system.
Note that most lab locations don’t accept walk-ins, so it’s best to book an appointment in advance. Don’t worry – we’ll provide detailed instructions along the way.
You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy!

754-799-7833

[email protected]

Blood Clotting Test for Warfarin Monitoring

Prothrombin Time (PT) (INR)

90 day happiness guarantee

Prescription & fees included

Easy to understand results

Fast & convenient

90 day happiness guarantee

Prescription & fees included

Easy to understand results

Fast & convenient

What's this test for?

How should I prepare for this test?

What's included in this test?

Here’s why 1,000,000+ customers chose us for affordable hassle-free private blood testing.

Blood Clotting Test for Warfarin Monitoring

90 day happiness guarantee

Prescription & fees included

Easy to understand results

Fast & convenient

1,000,000+ blood tests later, here's what our customers say