Prothrombin Time Test and INR (PT/INR)

What is a prothrombin time test with an INR?

The prothrombin time is a blood test to measure the time for blood clotting. An INR (International Normalized Ratio) is a method of calculation that depends on the PT test results. The PT test uses to diagnose blood disorders or excessive clotting disorders.

When you get injured or a cut that leads to bleeding, your body follows a process that makes clots to stop the bleeding. That process contains proteins known as clotting factors or coagulation factors. The liver produces prothrombin, a protein. Prothrombin is one of the elements of clotting factors that makes a connection for building blood clots. If you don’t have each recommended clotting factor and the function of these factors disturbs, then the clothing process does not work in a proper way.

The time for blood clotting varies on the number of clotting factors in your blood. You may experience excessive bleeding after an injury if your blood clots in more time. Dangerous clots may deposit in your arteries or veins when blood clotting occurs in less time. The PT test determines whether a medicine that prevents blood clots plays its part in the treatment. High PT levels indicate that your body takes more time than recommended to develop blood clots. 

Does this test have other names?

PT time, prothrombin time/international normalized ratio.

What is the purpose of the PT test?

The prothrombin time test indicates and diagnoses the following:
 

• The working of warfarin, which is a blood-thinning medicine. It is used for treatment and helps in blood clotting. 
• Causes for abnormal blood clots.
• Reasons for unexpected bleeding.
• Observe the working function of clotting before the surgery.
• Liver-related diseases.

When do I need the PT with an INR test?

Your provider recommends the test to measure the prothrombin levels in your blood when you already take the blood thinner warfarin. Warfarin helps to prevent blood clots, but it leads to several conditions, including deep venous thrombosis or pulmonary embolism. 

There are many other reasons that your provider asks you to conduct the prothrombin time test. Some symptoms of bleeding or clotting disorder are
Symptoms of bleeding disorder
 

• You experience bruises that mean cuts or bleeding in the nose that doesn’t stop. The PT test determines the cause to your provider for treatment purposes.
• Unexplained bleeding. The prothrombin test is the first way to indicate potential problems. 
• Unusual heavy menstrual periods in women

Symptoms of clotting disorders, such as
 

• Swelling and pain in the leg
• Tenderness
• Difficulty breathing
• Pain in chest
• Redness on the legs
• Increased heartbeat
• Cough

Besides, when you go through surgery, the functions of your blood clotting process are determined with the prothrombin test. You may need additional testing to observe your condition when your healthcare provider identifies that you have other health issues, including liver problems or bleeding disorders. 

What happens during the PT/INR test?

There are two ways to conduct this test, a blood sample from a vein or a fingertip.

Blood sample from a vein

Your healthcare provider asks for a blood sample. They inject a small needle into a vein in your arm to collect the blood in a test tube or container. You can return home for daily activities. This test finishes within 5 minutes. 

Blood sample from a fingertip:

You can place the order for a fingertip test at your home or at a provider’s location. Your provider can recommend the test at home with a PT test kit if you take warfarin to check your blood on a regular basis. Following are the steps for a fingertip test:
 

• A small needle helps to puncture your fingertip.
• A drop of blood collects into a test strip or other specific container.
• The test strip places into a device that measures the results. 

You will need to understand your test results with your provider if you are conducting the test using an at-home test kit. Your provider will inform you about how to get the test results. 

How do I need to prepare for the prothrombin time test?

You may ask to stop taking the daily dose of warfarin medicine before testing. You have to follow any specific instructions that your provider will recommend to you. 

What are the risks to the PT test?

A blood test has a low risk. You may experience a little pain or bruise near the point in your vein where the needle goes in. These symptoms do not stay for a long time. 

What is the normal range for the prothrombin time test?

The test results may indicate several ranges for PT and INR. The recommended value for clotting is 11 to 13.5 seconds and for INR is 0.8 to 1.1. For people who take warfarin, their INR value lies between 2 to 3. 

What does the PT test result mean?

The test results depend on the use of warfarin. If you are using warfarin, you will receive your results in INR levels, which is easier to compare results from different labs. The PT test results can be reported as INR levels or the time in seconds for blood clotting if you are not using warfarin. 

When you are taking warfarin
 

• Low INR levels indicate that you have a high probability of harmful blood clots.
• High INR levels show that you are at risk for developing excessive bleeding.

If you don’t take warfarin and your PT tests are not under ideal conditions, it can indicate the following possible condition:
 

• A bleeding disorder is a disease in which your body does not clot blood in a proper way, which results in excessive bleeding.
• Excessive clots deposit in arteries or veins due to a clotting disorder.
• Liver disease
• The deficiency of vitamin K helps in blood clotting.

What else do I need to know before the PT test?

The prothrombin time test often conducts with a partial thromboplastin time (PTT) test. It also observes clotting problems in a person. 

You can place an online order for the lab test at UmbrellaMD, even if you don’t have a prescription. You can also make an online appointment with a doctor here to get detailed information about your test results. Umbrella Health Care Systems is the online platform that establishes an online connection between a doctor and a sufferer. You can register to learn about more laboratory tests, medical imaging, e-consultation, and other services.