Prothrombin

Prothrombin is a protein produced by the liver that plays a critical role in blood clotting. When you cut or bleed, prothrombin helps form a clot by converting into another substance called thrombin. Thrombin then transforms fibrinogen into fibrin, which creates a mesh to stop bleeding. The body normally maintains a balance to ensure blood clots only when needed. Prothrombin levels can be measured with a blood test to assess clotting ability, and abnormal levels may indicate bleeding problems or a risk of abnormal clot formation.