Causes of increasing and decreasing blood coagulation time
Last reviewed: 23.04.2024
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The beginning of blood coagulation in a healthy person is from 30 seconds to 2 minutes, the end from 3 to 5 minutes. Blood is taken from the finger into a clean and dry capillary from the apparatus of Panchenkov. The first drop of blood is removed with a swab, then a column of blood 25-30 mm high is inserted into the capillary and transferred to the middle of the capillary tube. Turn on the stopwatch and after every 30 seconds, tilt the capillary at an angle of 30-45 °. Blood freely moves inside the capillary. With the beginning of clotting, its movement slows down. At the time of complete clotting, the blood stops moving.
Blood coagulation time is an indicative measure of a multistage enzymatic process, as a result of which soluble fibrinogen passes into insoluble fibrin. This indicator characterizes the process of coagulation as a whole and does not give an opportunity to reveal the mechanisms leading to its violation.
The time of blood coagulation can be shortened only as a result of the acceleration of the formation of blood prothrombinase (phase I of coagulation - increased contact activation, a decrease in the level of anticoagulants). Therefore, shortening the time of blood coagulation always indicates an increased formation of prothrombinase in the patient's body. Due to the fact that the blood prothrombinase can be easily replaced with a tissue one for strengthening the clotting processes, the formation of which terminates 2-4 times faster (in 1-2 minutes), the shortening of the clotting time is often caused by the appearance in the bloodstream of tissue thromboplastin due to mechanical damage to tissues, burns, extensive surgeries, transfusion of incompatible blood, sepsis, vasculitis, etc. Shortening of the clotting time indicates the need for prevention of hypercoagulability, which often threatens thrombosis and t omboemboliey.
Blood clotting is significantly slowed down by congenital or acquired deficiency of prothrombogenesis factors (primarily VIII, IX and XI), with an increase in the concentration of anticoagulants in blood, as well as fibrinogen and fibrin (PDF) degradation products.
Diseases and conditions accompanied by a change in clotting time
| Increase the coagulation time | Reducing the coagulation time |
|
Significant deficiency of plasma factors (IX, VIII, XII, I, factors included in the prothrombin complex) Hereditary coagulopathies Disturbances in the formation of fibrinogen Diseases of the liver Treatment with heparin Circulating anticoagulants |
Hypercoagulation after massive bleeding, postoperative and postpartum periods I stage (hypercoagulable) of DIC syndrome Side effect of oral contraceptives |
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