A prothrombin time (PT) measures how long it takes your blood to clot. It is used to help detect and diagnose the cause of unexplained bleeding or inappropriate blood clots. The international normalized ratio (INR) is a calculation based on results of a PT and is used to monitor individuals who are being treated with the blood-thinning medication (anticoagulant) warfarin.
Who needs a Protime/INR test?
A PT and INR are needed on a regular basis when a person is taking the anticoagulant drug warfarin to ensure that the prescription is working properly and that the PT/INR is appropriately prolonged, although there is no set frequency for doing the test.
If a person is not taking anticoagulant drugs, a PT/INR may be needed when signs or symptoms of excessive bleeding or clotting occur, such as:
- Unexplained bleeding or easy bruising
- Bleeding gums
- A blood clot in a vein or artery
- An acute condition such as disseminated intravascular coagulation (DIC) that may cause both bleeding and clotting as coagulation factors are used up at a rapid rate
- A chronic condition such as severe liver disease that may affect hemostasis
What should I do with my results?
It is always recommended you meet with a healthcare provider to determine what your laboratory test results mean to you. Your healthcare provider will review all of your test results and, combined with your health history, will be able to provide an accurate picture of your health status.
For a person who is not on a blood-thinning medication, the normal reference range is 0.9-1.1. For someone who is taking blood-thinning medicine, your healthcare provider will most likely choose to keep your INR between 2.0 and 3.0.
If your results were abnormal or out-of-range: If you are not taking blood-thinning medication, an INR above 1.1 means your blood is clotting more slowly than normal. This may be due to a bleeding disorder, a disorder in which the proteins that control blood clotting become over active, liver disease, or a low level of vitamin K.
If you are taking a blood-thinning medicine, INR results higher than 3.0 may put you at a higher risk for bleeding, while INR results below 2.0 may put you at risk for developing a blood clot. As with any abnormal results, it is important that you discuss the results with your healthcare provider.
How do I get tested?
To order your own lab tests, you just need to follow these three easy steps:
- Complete a lab order form for your test online and print it out to take with you to the DLO Patient Service Center. Follow the instructions on the laboratory test order form if fasting is required for the testing you are ordering.
- Visit any DLO Patient Service Center throughout Oklahoma. Check in with our friendly staff and give them your completed order form. Full payment is due at time of service before sample collection is performed. Note that we accept all major credit cards and checks. Unfortunately, we cannot accept cash payments. Have one of our skilled phlebotomists draw a blood sample or take a urine sample, who will send your sample to our laboratory for testing.
- Create a MyQuest™ account and view your test results through the MyQuest online patient portal. Test results are available through MyQuest within 7-10 business days of completing your lab work.
What other resources are available to learn more about my health and laboratory tests?
DLO Direct™ offers direct access to laboratory testing for informational purposes only. A DLO Direct lab test result is not a medical diagnosis and is not intended as medical advice. Only a healthcare provider can interpret lab results and diagnose a medical condition or disease.
Because tests have not been ordered by a healthcare provider, third party entities, including Medicare and Medicaid, will not reimburse for these tests.