International normalized ratio (INR)

International Normalized Ratio (INR) is a calculated indicator based on Prothrombin Time (PT), used to standardize blood coagulation test results between different laboratories and analytical methods. INR provides information about the activity of the extrinsic and common coagulation pathways and is primarily used for monitoring treatment with oral anticoagulants that are vitamin K antagonists.

INR values may be influenced by anticoagulant therapy, liver disease, vitamin K deficiency, and other coagulation disorders.

Indications

• monitoring of treatment with oral anticoagulants that are vitamin K antagonists, as recommended by a physician;
• assessment of the blood coagulation system;
• investigation of bleeding or bruising of unclear origin;
• assessment of the risk of coagulation disorders;
• evaluation of the function of coagulation factors involved in the extrinsic and common coagulation pathways;
• assessment of liver synthetic function in a clinical context;
• preoperative assessment, as recommended by a physician;
• monitoring of patients with conditions that may affect blood coagulation;
• other clinical situations, as recommended by a physician.

Procedure

The test is performed using a venous blood sample. INR is calculated based on the Prothrombin Time result and parameters specific to the analytical method used.

Sources:

https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=international_normalized_ratio
https://www.ncbi.nlm.nih.gov/books/NBK507707/
https://www.hepatitis.va.gov/hcv/patient/diagnosis/labtests-INR.asp/
https://medlineplus.gov/lab-tests/prothrombin-time-test-and-inr-ptinr/

IMPORTANT!

It is crucial to remember that the information provided in this section is not intended for self-diagnosis or self-treatment. If you experience any pain or exacerbation of a condition, it is essential to consult a healthcare professional for proper diagnosis and treatment recommendations. Only a qualified specialist can accurately diagnose and determine the appropriate course of treatment. To ensure the most accurate and consistent evaluation of test results, it is recommended to have them performed at the same laboratory. This is because different laboratories may use varying methods and units of measurement for similar tests.