Prothrombin Time with INR Test

Are you taking warfarin (a type of medication known as a blood thinner which can treat and prevent blood clots)? Our Prothrombin Time with INR (PT/INR) Test can help measure how long it takes for your blood to clot and help you and your healthcare provider monitor medication in your blood.
+ $6.00 Physician Service Fee

Who is getting tested? *

Test Type

Unfortunately this test is not right for you based on your responses.
Our PT/INR Test measures how long it takes for blood to clot.

Must be 18+ years of age to purchase

Orders not permitted in: AK, HI, AZ

Type of sample to be collected:
Blood (venipuncture - a needle is used to draw blood from a vein)
Schedule an appointment, then visit one of our Patient Service Centers.
About the Test

Our Prothrombin Time with INR (PT/INR) Test measures how long it takes for your blood to form a clot (coagulate). Anticoagulants (anti-clotting medications) change the way your blood clots. Warfarin is a commonly prescribed anticoagulant, or blood thinner, that prevents blood from clotting. Anticoagulant therapy must be carefully monitored to make sure the dosage is right for the patient; otherwise, severe and persistent bleeding or excessive blood clotting (hypercoagulation) can occur.

Lab technician

How Does it Work?
Take an in-person test at a Quest Diagnostics location.
Over 2000+ locations focus on your safety, confidentiality and convenience.
1. Purchase your test
Schedule your appointment after purchasing a test to minimize wait time.
2. Visit a location
Enter your zip code to find a Quest Diagnostics location closest to you.
3. Get results online
We will email you when your confidential results are available. 

The benefits of testing

You can get the information you need to support a healthy life - for yourself.

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Take control of your health

Conveniently shop and pay online for lab tests without a doctor's visit. An independent physician will review your request and if appropriate, confirm your order and offer oversight.

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Schedule and manage your appointments

Conveniently schedule your appointment online at one of our Quest Diagnostics locations. Certain tests may also offer self-testing home delivery.

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Get your results online

View your results through your secure account online. And it's easy to share the result with your doctor.