Lab test
Prothrombin Time (PT) with INR & PTT
This panel combines the prothrombin time (PT), the International Normalized Ratio (INR), and the partial thromboplastin time (PTT) to evaluate how well blood clots.
- Typical price
- From $49
- Results
- 1-3 business days
- Preparation
- See preparation notes below
- Sample
- Blood draw or sample collection at a local center
About this test
This panel combines the prothrombin time (PT), the International Normalized Ratio (INR), and the partial thromboplastin time (PTT) to evaluate how well blood clots. The PT and INR assess the extrinsic and common clotting pathways and are used to monitor warfarin, while the PTT assesses the intrinsic and common pathways and is often used to monitor heparin. Together they help investigate bleeding, bruising, and clotting disorders and are checked before some procedures.
What this test measures
- Prothrombin Time (PT) Measures clot formation through the extrinsic and common pathways.
- International Normalized Ratio (INR) A standardized form of the PT used to compare results and monitor warfarin.
- Partial Thromboplastin Time (PTT) Measures the intrinsic and common pathways and is often used to monitor heparin.
Who this test may be right for
- People taking warfarin, heparin, or similar anticoagulants
- Individuals with unexplained bleeding or easy bruising
- Patients with a suspected bleeding or clotting disorder
- People with liver disease affecting clotting factors
- Patients being assessed before surgery or invasive procedures
Before your visit
- Report all anticoagulant and other medications
- Avoid major dietary changes and excess alcohol before testing unless advised
- No fasting is usually required
- Collect at the time recommended for monitoring your therapy
Understanding your results
A prolonged PT or high INR can indicate a bleeding tendency or the effect of warfarin, while a prolonged PTT may reflect heparin therapy or a factor deficiency in the intrinsic pathway. Abnormal results are interpreted together and with your medications, liver function, and symptoms. Discuss your PT, INR, and PTT results and any treatment adjustments with a healthcare provider.
Order this test online
- Buy online in a few minutes - no doctor's visit needed for most tests.
- Sample collection at a patient service center near you.
- Results are typically ready within 1-3 business days.
- Secure, lab-reviewed results delivered to your account.
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Questions people ask
What is the difference between PT/INR and PTT?
PT and INR evaluate the extrinsic and common clotting pathways and are used to monitor warfarin. PTT evaluates the intrinsic and common pathways and is often used to monitor heparin.
Do I need to fast for this panel?
Fasting is usually not required. Follow any specific instructions provided with your order.
Why would my provider order all three tests?
Ordering PT, INR, and PTT together gives a broader view of the clotting system and helps identify which pathway may be affected.
Can medications change my results?
Yes. Anticoagulants and some other medications affect clotting tests. Report everything you take so results can be interpreted correctly.
What does the Prothrombin Time (PT) with INR & PTT measure?
Order Prothrombin Time (PT) with INR & PTT.com online through our partner and visit a local lab near you.
Do I need to fast before this test?
Follow the lab's instructions.
How long do results take?
Most Prothrombin Time (PT) with INR & PTT results are released in 1-3 business days. Specialty testing can take longer.
Is this test right for me?
This page is educational and not medical advice. Talk to a licensed healthcare provider about which tests fit your situation.
LabBookings is an independent directory. We compare test details and pricing information, but we are not a laboratory and we do not perform testing or provide medical advice. Always talk to a licensed healthcare provider about your results and treatment.
Laboratory services are provided by independent, CLIA-certified testing partners. Availability, pricing, and turnaround times can vary by location and are confirmed at checkout.