Basics of Coagulation: Medical information to help you stay in control

More and more people require life-long oral anticoagulation (Vitamin K Antagonists, also called coumarin derivatives) as a result of various medical conditions such as mechanical heart valves, atrial fibrillation or other conditions promoting the formation of potentially dangerous blood clots or thrombi.

Since everyone reacts differently to these drugs and many interferences exist such as diet, stress, other drugs, etc., the periodic measurement of Prothrombin Time (PT) or International Normalized Ratio (INR) is the test performed to adjust dosage of oral anticoagulation therapies to the proper individual "therapeutic range". This therapeutic range will be defined by your doctor or healthcare professional, who will need the PT/INR tests to monitor it.