| In the second stage, prothrombin is activated by thromboplastin to make thrombin. |
| The atrial fibrillation group also had more hematologic tests done, including more prothrombin and partial thromboplastin times. |
| The prothrombin test is one measure of how long it takes your blood to begin clotting. |
| This complex activates prothrombin to thrombin in the presence of calcium ions. |
| The next to last step in this chain is the activation of the circulating proenzyme prothrombin into its active form, thrombin. |
| Contact with tissue factor triggers the coagulation cascade, resulting in the conversion of prothrombin to active thrombin. |
