Definition
Definition
Thrombin time is the time it takes for blood plasma to clot in the presence of thrombin. It depends on the amount of fibrinogen present in the blood, as well as the levels of antithrombin and heparin in the plasma. This time is normally 2 to 4 seconds.
Symptoms
physiology
Thrombin is an enzyme ( a type of protein that enables certain biochemical reactions in the body) that is produced by the activation of prothrombin by thromboplastin , provided that there are calcium ions (calcium atoms that have lost two electrons), and other types of proteins called accelerators:
In other words, thrombin is an enzyme whose main action is the transformation of fibrinogen into fibrin. This step is the last in the process of plasma coagulation, that is, the coagulation of the liquid part of the blood.
To understand the process involving thrombin, it is necessary to know that another protein, prothrombin , is the precursor to thrombin. In the presence of vitamin K in the blood, prothrombin is synthesized by the liver and then activated to produce thrombin.
This prothrombin is transformed into thrombin by the help of another protein called coagulation factor X, which is activated only if there is calcium in the blood , and another factor called factor V, which plays a catalytic role (a chemical substance that allows the rate of a chemical reaction to be changed by undergoing significant changes itself).
Pathophysiology
Thrombin time allows the diagnosis of abnormalities in fibrinogen formation , and to find if there are products that cause its degradation.
The fibrin time indirectly detects the presence of a myeloma protein which, if detected, can lead to a diagnosis of multiple myeloma , also known as Kahler's disease . This disease is the abnormal proliferation of plasma cells (a type of white blood cell) in the bone marrow , the origin of which is unknown . Affecting approximately 7 out of 10,000 people annually, it most often begins after age 50 and is twice as common in men as in women. The proliferation of plasma cells results in an overproduction of antibodies (or immunoglobulins), each type of which corresponds to a specific myeloma. Plasma cells also produce substances that can destroy bone tissue.
Medical exam
Labo
Measuring the thrombin time allows for the overall assessment of fibrin, which is one of the stages of coagulation during which, thanks to the intervention of an enzyme (thrombin), fibrinogen will transform into fibrin (a protein substance whose filaments reinforce the platelet plug, i.e. the gathering of platelets intended to block the orifice causing a hemorrhage).
The thrombin time is a test that bypasses all the coagulation stages that occurred before it. These stages are measured by the prothrombin time and the cephalin time.