Prothrombin Time (PT) INR
Other names: International normalised ratio, PROTHROMBIN TIME-INR, INR
Prothrombin time (PT) is a blood test that measures the time it takes for the liquid portion (plasma) of your blood to clot. A prothrombin time test can be used to check for bleeding problems. PT is also used to check whether medicine to prevent blood clots is working. A PT test may also be called an INR test. INR stands for 'international normalized ratio'.
The INR is typically used to monitor patients on warfarin or related oral anticoagulant therapy. The normal range for a healthy person not using warfarin is 0.8–1.2, and for people on warfarin therapy an INR of 2.0–3.0 is usually targeted, although the target INR may be higher in particular situations, such as for those with a mechanical heart valve. If the INR is outside the target range, a high INR indicates a higher risk of bleeding, while a low INR suggests a higher risk of developing a clot.
What does it mean if your Prothrombin Time (PT) INR result is too high?
An elevated Prothrombin Time (PT) and International Normalized Ratio (INR) indicate that the blood is taking longer to clot than the normal range.
PT measures the time it takes for your blood to clot. The normal range for PT is typically 10 to 13 seconds in most laboratories. An elevated PT suggests that your blood is clotting more slowly than usual.
INR is a standardized way of reporting PT results, which helps ensure consistency across different laboratories. A healthy individual typically has an INR of 1.1 or below. An INR higher than 1.1 indicates slower blood clotting.
Causes of Elevated PT/INR: Several factors can lead to an elevated PT/INR, including liver disease, vitamin K deficiency, certain medications (such as blood thinners), and clotting disorders.
Clinical Significance: An elevated PT/INR can increase the risk of bleeding because it indicates impaired blood clotting ability. It is essential to consult a healthcare provider to determine the underlying cause and appropriate treatment.
All Your Lab Results.
One Simple Dashboard.
Import, Track, and Share Your Lab Results Easily
Import, Track, and Share Your Lab Results
Import lab results from multiple providers, track changes over time, customize your reference ranges, and get clear explanations for each result. Everything is stored securely, exportable in one organized file, and shareable with your doctor—or anyone you choose.
Cancel or upgrade anytime
What does it mean if your Prothrombin Time (PT) INR result is too low?
Understanding Low INR Levels: With and Without Warfarin Therapy
INR (International Normalized Ratio) is a blood test that measures how long it takes your blood to clot. It's primarily used to monitor warfarin (a blood thinner) but can also provide insight into clotting function in people not taking anticoagulants.
If You Are on Warfarin Therapy
Target INR Range: Typically 2.0 to 3.0, depending on your condition.
What a Low INR Means (Below 2.0):
-
Your blood is not thin enough, which increases the risk of blood clots.
-
This can lead to serious health issues such as stroke, pulmonary embolism, or deep vein thrombosis.
What to Do:
-
Contact your doctor or anticoagulation clinic immediately. Do not adjust your dose without medical supervision.
-
Review possible causes, such as:
-
Missed warfarin doses
-
Increased intake of vitamin K (e.g., leafy greens)
-
Interactions with new medications or supplements
-
-
Follow up with repeat INR testing as recommended by your healthcare provider.
If You Are Not on Warfarin
A low INR (typically below 0.8) means your blood clots faster than average.
Possible Causes:
-
High vitamin K intake
-
Dehydration
-
Lab variability or error
-
Rare clotting disorders or inherited thrombophilia (though these are usually diagnosed through other tests)
When to Be Concerned:
-
Most healthy individuals with a slightly low INR and no symptoms do not need treatment.
-
Persistent low INR or symptoms such as unexplained blood clots may warrant further evaluation by your doctor.
Summary
-
For people on warfarin, a low INR means insufficient blood thinning and a higher risk of clot formation. Prompt medical follow-up is essential.
-
For people not on anticoagulants, a low INR usually isn't concerning unless accompanied by symptoms or an underlying health condition.
Always interpret INR results with your healthcare provider, who can assess them in the context of your overall health and treatment goals.
Laboratories
Bring All Your Lab Results Together — In One Place
We accept reports from any lab, so you can easily collect and organize all your health information in one secure spot.
Pricing Table
Gather Your Lab History — and Finally Make Sense of It
Finally, Your Lab Results Organized and Clear
Personal plans
$79/ year
Advanced Plan
Access your lab reports, explanations, and tracking tools.
- Import lab results from any provider
- Track all results with visual tools
- Customize your reference ranges
- Export your full lab history anytime
- Share results securely with anyone
- Receive 5 reports entered for you
- Cancel or upgrade anytime
$250/ once
Unlimited Account
Pay once, access everything—no monthly fees, no limits.
- Import lab results from any provider
- Track all results with visual tools
- Customize your reference ranges
- Export your full lab history anytime
- Share results securely with anyone
- Receive 10 reports entered for you
- No subscriptions. No extra fees.
$45/ month
Pro Monthly
Designed for professionals managing their clients' lab reports
- Import lab results from any provider
- Track lab results for multiple clients
- Customize reference ranges per client
- Export lab histories and reports
- Begin with first report entered by us
- Cancel or upgrade anytime
About membership
What's included in a Healthmatters membership
Import Lab Results from Any Source
See Your Health Timeline
Understand What Your Results Mean
Visualize Your Results
Data Entry Service for Your Reports
Securely Share With Anyone You Trust
Let Your Lab Results Tell the Full Story
Once your results are in one place, see the bigger picture — track trends over time, compare data side by side, export your full history, and share securely with anyone you trust.
Bring all your results together to compare, track progress, export your history, and share securely.
What Healthmatters Members Are Saying
Frequently asked questions
Healthmatters is a personal health dashboard that helps you organize and understand your lab results. It collects and displays your medical test data from any lab in one secure, easy-to-use platform.
- Individuals who want to track and understand their health over time.
- Health professionals, such as doctors, nutritionists, and wellness coaches, need to manage and interpret lab data for their clients.
With a Healthmatters account, you can:
- Upload lab reports from any lab
- View your data in interactive graphs, tables, and timelines
- Track trends and monitor changes over time
- Customize your reference ranges
- Export and share your full lab history
- Access your results anytime, from any device
Professionals can also analyze client data more efficiently and save time managing lab reports.
Healthmatters.io personal account provides in-depth research on 10000+ biomarkers, including information and suggestions for test panels such as, but not limited to:
- The GI Effects® Comprehensive Stool Profile,
- GI-MAP,
- The NutrEval FMV®,
- The ION Profile,
- Amino Acids Profile,
- Dried Urine Test for Comprehensive Hormones (DUTCH),
- Organic Acids Test,
- Organix Comprehensive Profile,
- Toxic Metals,
- Complete Blood Count (CBC),
- Metabolic panel,
- Thyroid panel,
- Lipid Panel,
- Urinalysis,
- And many, many more.
You can combine all test reports inside your Healthmatters account and keep them in one place. It gives you an excellent overview of all your health data. Once you retest, you can add new results and compare them.
If you are still determining whether Healthmatters support your lab results, the rule is that if you can test it, you can upload it to Healthmatters.
We implement proven measures to keep your data safe.
At HealthMatters, we're committed to maintaining the security and confidentiality of your personal information. We've put industry-leading security standards in place to help protect against the loss, misuse, or alteration of the information under our control. We use procedural, physical, and electronic security methods designed to prevent unauthorized people from getting access to this information. Our internal code of conduct adds additional privacy protection. All data is backed up multiple times a day and encrypted using SSL certificates. See our Privacy Policy for more details.