PT / PTT are laboratory tests that measure the clotting time (how long it takes blood to clot.) PT / PTT are blood tests and INR is a ratio calculated from the PT.
What is the normal PT PTT INR value?
What are normal results for a PT test? Prothrombin time test results are given in a measurement called an INR (international normalized ratio). The normal range for clotting is: 11 to 13.5 seconds; INR of 0.8 to 1.1; For patients on warfarin, the therapeutic range is 2.0 to 3.0. What can cause PT test results to be outside the normal range?
What do your PT, PTT, and INR results mean?
The prothrombin time (PT) test measures how quickly blood clots. The partial thromboplastin time (PTT) is mainly used to monitor a person's response to heparin. The international normalized ratio (INR) test ensures that PT results are standardized and is the test of choice for people on vitamin K antagonists.
What is the normal range of PT INR?
What is the normal range of PT INR? Most of the time, results are given as what is called INR (international normalized ratio). If you are not taking blood thinning medicines, such as warfarin, the normal range for your PT results is: 11 to 13.5 seconds. INR of 0.8 to 1.1. Besides, what is the normal range of INR?
What causes elevated PT INR?
What causes elevated INR? For some who have a high risk of a blood clot, the INR needs to be higher - about 2.5 to 3.5. This may be caused by conditions such as liver disease, vitamin K deficiency, or a coagulation factor deficiency (e.g., factor VII deficiency). Further detail about this can be seen here.
What is the difference of PT and INR?
A prothrombin time (PT) test measures how long it takes for a clot to form in a blood sample. An INR (international normalized ratio) is a type of calculation based on PT test results. Prothrombin is a protein made by the liver. It is one of several substances known as clotting (coagulation) factors.
What is PT INR aPTT?
The Prothrombin Time (PT/INR) and Partial Thromboplastin Time (PTT) test is used to measure how long it takes the blood to clot. These two tests, combined, are needed to initiate an investigation when there is unexplained bleeding or clotting.
Why is INR used instead of PT?
A prothrombin time (PT) is a test used to help detect and diagnose a bleeding disorder or excessive clotting disorder; the international normalized ratio (INR) is calculated from a PT result and is used to monitor how well the blood-thinning medication (anticoagulant) warfarin (Coumadin®) is working to prevent blood ...
Is INR and aPTT the same?
The PT/INR is used to assess the extrinsic or tissue factor pathway, while the aPTT is used to assess the function of the intrinsic or contact pathway of coagulation (4). Deficiencies in the common pathway are associated with prolongations of both the PT/INR and aPTT (4).
How do I remember PT PTT INR?
The keyword is weird....PT also measures clotting times.Pills TakIN Regularly -PT and INR go together.INR--I=normal is 1, but therapeutic ranges from 2 (NR, 2 letters after the I) to 3 (INR, 3 letters in total)Usually measured when on Coumadin / Warfarin.Think Wiz Khalifa--Warfarin (vitamin) K to remember the antidote.More items...•
What is normal PT INR?
Most of the time, results are given as what is called INR (international normalized ratio). If you are not taking blood thinning medicines, such as warfarin, the normal range for your PT results is: 11 to 13.5 seconds. INR of 0.8 to 1.1.
What does PTT test for?
A partial thromboplastin time (PTT) test measures the time it takes for a blood clot to form. Normally, when you get a cut or injury that causes bleeding, proteins in your blood called coagulation factors work together to form a blood clot. The clot stops you from losing too much blood.
Why is PT not used for heparin?
Heparin typically prolongs the aPTT alone (because PT reagents contain heparin-binding agents that block heparin effect), but at high levels heparin can prolong both tests. Direct thrombin inhibitors (argatroban, dabigatran) typically prolong both tests, but at low levels dabigatran may not prolong the PT.
What does low INR and high PT mean?
In certain situations, such as having a mechanical heart valve, you might need a slightly higher INR. When the INR is higher than the recommended range, it means that your blood clots more slowly than desired, and a lower INR means your blood clots more quickly than desired.
Is PT and PTT the same?
The prothrombin time (PT) test measures how quickly blood clots. The partial thromboplastin time (PTT) is mainly used to monitor a person's response to anticoagulant therapies.
What is difference between PT and aPTT?
The prothrombin time (PT) is a plasma and test tube test of the integrity of the extrinsic pathway, and the activated clotting time or activated partial thromboplastin time (aPTT) are tests of the intrinsic system for blood and plasma, respectively.
What is difference between PT & aPTT?
Description. Partial thromboplastin time (PTT) and activated partial thromboplastin time (aPTT) are used to test for the same functions; however, in aPTT, an activator is added that speeds up the clotting time and results in a narrower reference range.
What is the INR in PT?
The international normalized ratio (INR) is used to make sure the results from a PT test are the same from one lab to another. In the 1980s, the World Health Organization determined that people undergoing surgery may be at risk of excessive bleeding because different labs had different standardized values than other labs. 9
What is a partial thromboplastin time test?
The partial thromboplastin time (PTT) test is performed primarily to determine if heparin therapy is effective 5 and it can also detect a clotting/bleeding disorder. However, it can't be used to monitor the effect of drugs such as Lovenox, which are used to prevent and treat blood clots in the legs and complications of heart disease. 6
What is a coagulation test?
Tests that assess blood clotting, known as coagulation studies, include prothrombin time (PT), partial thromboplastin time (PTT), and international normalized ratio (INR). You may need one or more of these tests to monitor an illness, follow the effects of blood thinner therapy, or as part of pre-surgical blood testing .
What is the name of the test that assesses blood clotting?
Ali is also an award-winning writer. Tests that assess blood clotting, known as coagulation studies , include prothrombin time (PT), partial thromboplastin time (PTT), and international normalized ratio (INR).
Do blood thinners make a clot?
Blood thinners and anticoagulants will make blood take longer to clot. If you are taking one of these medications, your results will likely be higher than the standard normal values, reflecting the longer time that it takes for your blood to form a blood clot. Making Sense of Blood Thinners For Surgery Patients.
Can you stop taking medications before a PTT?
Several conditions and medications can impact your PTT test results, including: Your doctor might ask you to stop taking certain drugs before your coagulation study. Do not stop taking any of your medications without your doctor's advice. 8.
Does warfarin affect INR?
Can your diet impact your INR levels? Yes, if you are taking warfarin, certain foods and drinks, that contain vitamin K, like dark leafy greens or green tea, may reduce its effectiveness. 14 Alcohol or cranberry and grapefruit products can increase the risk of bleeding when taking warfarin. 15.
What is the difference between PT and INR?
PT and INR are both measures of how long it takes your blood to clot, expressed in two different ways. PT stands for prothrombin time. It is a measure in seconds of how long it takes your blood to clot. The INR is a formula that allows for differences between laboratories so that test results can be compared. Click to see full answer.
What is the range of PT and INR?
Subsequently, question is, what is the normal range for PTT and INR? If you are not taking blood thinning medicines, such as warfarin, the normal range for your PT results is: 11 to 13.5 seconds.
What is the difference between PT and prothrombin time?
Partial thromboplastin time (PTT) measures the overall speed at which blood clots by means of two consecutive series of biochemical reactions known as the intrinsic pathway and common pathway of coagulation. The prothrombin time (PT) measures the speed of clotting by means of the extrinsic pathway.
Could you explain to me the difference between pt, ptt, and inr?
Complicated: Prothrombin Time (PT) measures clotting factors: V, VII, X, prothrombin and fibrinogen . The raw number is of no value. A system of comparing it to a standardized control (used internationally) is generated as the INR (international normalized ratio).
Could a doctor please explain to me the difference between pt, ptt, and inr?
PT, PTT, INR: PT or prothrombin time and INR or International Normalized Ratio are used to test the anticoagulant effect of warfarin, PTT or partial thromboplastin time is a more general test of adequacy of clotting factors.
What is the difference between PT and INR?
A prothrombin time (PT) test measures how long it takes for a clot to form in a blood sample. An INR (international normalized ratio) is a type of calculation based on PT test results. Prothrombin is a protein made by the liver. It is one of several substances known as clotting (coagulation) factors.
Why do we use INR?
INR levels are often used because they make it easier to compare results from different labs and different test methods. If you are not taking warfarin, your results may be in the form of INR levels or the number of seconds it takes for your blood sample to clot (prothrombin time). If you are taking warfarin:
What does it mean when you don't take prothrombin?
If you are not taking warfarin and your INR or prothrombin time results were not normal, it may mean one of the following conditions: A bleeding disorder, a condition in which the body can't clot blood properly, causing excessive bleeding. A clotting disorder, a condition in which the body forms excessive clots in arteries or veins. Liver disease.
What does it mean when INR is too low?
If you are taking warfarin: INR levels that are too low may mean you are at risk for dangerous blood clots. INR levels that are too high may mean you are at risk for dangerous bleeding. Your health care provider will probably change your dose of warfarin to reduce these risks.
Why do you need a blood test for warfarin?
The test helps make sure you are taking the right dose. If you are not taking warfarin, you may need this test if you have symptoms of a bleeding or clotting disorder. Symptoms of a bleeding disorder include: Unexplained heavy bleeding.
How to get blood test results?
Use a small needle to puncture your fingertip. Collect a drop of blood and place it onto a test strip or other special instrument. Place the instrument or test strip into a device that calculates the results. At-home devices are small and lightweight.
How to test blood from fingertip?
If you are taking warfarin, your provider may recommend you test your blood regularly using an at-home PT/INR test kit. During this test, you or your provider will: Use a small needle to puncture your fingertip.

What Is Coagulation?
Purpose of Testing
- Coagulation studies are used to evaluate blood clotting based on how fast clotting occurs in a sample of blood. All that is required is a simple blood draw. Prior to the test, your healthcare provider may ask you to stop taking certain medications that can affect the results.1 The tests can identify clotting problems and measure your response to therapies such as blood thinners o…
Types of Test
- Two of the tests used in a coagulation study—prothrombin time (PT) and partial thromboplastin time (PTT, also known as aPTT)—can reveal specific things about your health. The third, called the international normalized ratio (INR), is technically a calculation more than it is a test. It is used to assess your response to blood thinners based on the ...
Risks and Complications
- Blood draws are routine, low-risk procedures. While rare, it is possible to have complications from a blood draw, including: 1. Injection site pain 2. Localized bruising 3. A blood-filled bump (hematoma) at the injection site 4. Lightheadedness or fainting 5. Excessive bleeding (especially if you’re taking blood thinners) 6. Infection (uncommon) If you feel lightheaded during or after a …
Summary
- Coagulation studies involve one or more blood tests that measure how quickly blood clots. The tests can help detect bleeding disorders, check a person’s response to anti-clotting or pro-clotting therapies, and assess a person’s risk for bleeding prior to surgery. Coagulation studies require a simple blood draw. The prothrombin time (PT) test measures the rate of blood clotting in secon…