Protrombiiniarvo

Protrombiiniarvo, also known as prothrombin time (PT), is a blood test used to measure the time it takes for blood to clot. This test assesses the functionality of the extrinsic and common pathways of the coagulation cascade, primarily evaluating the activity of clotting factors I (fibrinogen), II (prothrombin), V, VII, and X.

The procedure involves collecting a blood sample and adding a reagent containing tissue factor and calcium to initiate clotting. The time taken for a clot to form is measured in seconds. The result is often expressed as an internationally normalized ratio (INR), which standardizes PT results regardless of testing methods. The INR is particularly important for monitoring patients on anticoagulant therapy, such as warfarin.

Prothrombin time can be influenced by various factors, including vitamin K deficiency, liver disease, certain medications, and clotting factor deficiencies. Abnormal PT results may indicate bleeding disorders, monitor anticoagulant therapy efficacy, or suggest underlying hepatic dysfunction.

Clinically, a prolonged PT may suggest an increased risk of bleeding, whereas a shortened PT is less common but may be associated with hypercoagulable states. The test is a vital component in assessing coagulation status, guiding treatment decisions, and diagnosing coagulation-related conditions.

Regular monitoring of PT/INR is essential for patients on anticoagulants to ensure therapeutic effectiveness while minimizing the risk of bleeding complications. The test is widely used in preoperative assessments and in the diagnosis of bleeding or thrombotic disorders.