INR (International Normalized Ratio)
INR is used for standardized assessment of the external blood coagulation pathway. Allows monitoring of anticoagulant therapy efficacy (e.g., warfarin), detection of coagulation disorders, and assessment of bleeding or thrombosis risk.
Test composition:
Material: venous blood
- Method: coagulometric method with INR calculation based on prothrombin time and international sensitivity index (ISI)
- Measured indicator: ratio of patient prothrombin time to reference value adjusted for ISI
- Deviation causes: elevated INR — slowed clotting, anticoagulant therapy, coagulation factor deficiency, or liver diseases. Reduced — elevated clotting and thrombosis risk.
Biomaterial: Venous blood
- Draw blood fasting
- Exclude alcohol 24 hours before
- Avoid physical activity and stress before testing
Medications:
Inform physician of anticoagulant, antiplatelet, or hormonal drug intake before testing
Prescribed for:
- Anticoagulant therapy monitoring
- Suspected blood clotting disorders
- Bleeding or thrombosis tendency
- Preoperative preparation
- Liver diseases and other systemic pathologies affecting coagulation
Recommended for:
- Patients taking anticoagulants
- People with hemostasis disorders
- Pre-surgery patients
Reference values depend on methodology used and are indicated on result form.
Deviations require physician consultation and comprehensive assessment.
Note: INR evaluated together with other coagulation indicators and not used as standalone diagnostic criterion.
With deviations, consultation with general practitioner, hematologist, or cardiologist is recommended.
