Back to basics ! Prothrombin time (PT) / International normalized ratio (INR): a time-honored global coagulation test

Prothrombin time (PT) and the International Normalized Ratio (INR) are vital tests for assessing blood clotting ability, guiding clinical decisions, monitoring anticoagulant therapy, evaluating liver function, and diagnosing bleeding disorders. PT measures the time taken for blood to clot, reflecting the extrinsic and common coagulation pathways, while INR standardizes results across different labs for patients on antivitamin K therapy (e.g. warfarin). However, there are certain pitfalls and challenges associated with PT/INR testing. Inter-laboratory variability, influenced by differences in reagents and calibration methods, can lead to discrepancies in reported results. Hematocrit levels, medication interference, sample collection errors, and patientspecific variations also pose challenges, emphasizing the importance of standardized protocols and careful consideration of clinical context during result interpretation. Interpreting PT/INR results involves understanding the therapeutic INR range for anticoagulant therapy, recognizing liver dysfunction implications, and diagnosing coagulation disorders. Preoperative PT/ INR testing aids in assessing surgical risk and guiding perioperative management.
During this webinar, clinicians, clinical pathologists, PhDs, clinical laboratory technicians and students will have the opportunity to find out on the PT/INR principle, indications, interpretation and pitfalls, based on the experience of Prof. Armando Tripodi.