Prothrombin time is the number of seconds that elapses between the start of the clotting process and the formation of a clot in the blood sample. Prothrombin is a protein produced in the liver. The INR (International Normalized Ratio) is a numerical value that allows different laboratories to balance the differences between prothrombin time reagents (reagent: a compound that reacts with another compound).
What is the purpose of the test?
The test can be used to check whether anticoagulants are effective enough to prevent blood clots from forming. The test is also helpful in diagnosing bleeding disorders.
When it is recommended to take the test?
The test is recommended if the patient has received an anticoagulant treatment containing a coumarin derivative (Marfarin, Warfarin, Syncumar).
What kind of sample is needed?
Plasma is required for the test. A blood sample taken in a citrate tube is ideal for extraction. Citrate prevents clotting. After removal, the blood in the tube is circulated so that the anticoagulant can work properly.
What does the result mean?
The values indicated on the report mean:
Prothrombin time (Pl): The time interval, expressed in seconds, from the start of the coagulation process to the formation of the clot.
The Prothrombin time depends on the method, the instrument and the reagent, which is why it is important to enter the INR value.
Prothrombin INR: the patient’s INR (International Normalized Rate)
For a patient treated with an anticoagulant, an anticoagulant setting is appropriate if the INR is between 2.0 and 3.0. In individuals with a high risk of coagulation, an INR of 2.5-3.5 is considered appropriate.
What should you do after your results arrive?
In all cases, please consult the specialist or internal physician who ordered the test with the result.