Prothrombin Time (PT/INR) Test

Prothrombin time test is used to calculate how well or how quickly the body forms clots in case of an injury. This may be done:

• In those suffering from bleeding disorders, where body bleeds excessively when injured
• In clotting disorders, where there are formation of excessive clots. 
• In those taking warfarin (anticoagulant) to assess its efficiency.
• Prior to surgeries to know the risk of bleeding.
• In liver disorders.

The Prothrombin Time (PT) test measures the time it takes for your blood plasma to form a clot. It essentially checks the efficiency of a specific pathway in your blood clotting system.

Prothrombin time test requires a blood sample. A tourniquet (elastic) band is placed tightly on the upper arm. The patient is then asked to make a fist. This helps in the build-up of blood filling the veins. The skin is disinfected before needle insertion and the blood sample is collected in vacutainer. 

Low PT indicates that the body is at a risk of forming excess blood clots which may mean a clotting disorder. High PT indicates delayed clotting which means that there is risk of bleeding excessively, occurs in cases of bleeding disorders. Vitamin K deficiency, liver disorders and certain medication like warfarin may also affect the PT.

There are no specific preparations required for the test. However, it is recommended that you consult with your healthcare provider before taking the test, as they may have specific instructions or recommendations based on your individual medical history and current health status. Mention the name of the medicine and its dose schedule in the test requisition form.

This test is similar to the other blood tests, so we need not worry. Any soreness or minor bruising at the blood collection site goes away with time.

Some foods rich in vitamin K can affect the results. Foods such as broccoli, chickpeas, green tea, soybean products, kale, chickpeas, turnip greens, asparagus, beef, and pork liver should be avoided.

PT (prothrombin time) and PTT (partial thromboplastin time) tests are both blood tests used to assess blood clotting, but they target different parts of the clotting cascade and provide information on distinct aspects of clotting function. PT test indirectly assesses prothrombin and other vitamin K-dependent clotting factors. While the PPT test evaluates a broader range of clotting factors compared to PT.

Haemophilia is an inherited bleeding disorder in which the blood fails to clot properly, thus leading to spontaneous bleeding.

There are 13 coagulation factors, out of which prothrombin (Factor II) is the most important.

A high PT level indicates that there is serious liver damage or cirrhosis.

• People with the following symptoms should do the PT test:
• Unusual heavy nose bleeds
• Unusual heavy menstrual periods in women
• Unexplained heavy bleeding or easy bruising
• Bleeding gums
• Leg pain, swelling, or redness
• Trouble breathing, cough, or chest pain
• Rapid heartbeat
• Swollen or painful joints
• Blood in the urine

• PT
• Pro Time
• Anticoagulant-prothrombin time
• Clotting time: protime
• INR
• International normalized ratio