Fibrinogen

Fibrinogen ( factor I) is a protein synthesized primarily in the liver. In blood, it is in a dissolved state, but as a result of the enzymatic process, under the influence of thrombin and factor XIIIa it can turn into insoluble fibrin. The reference values ​​of the fibrinogen concentration in the blood plasma are given in the table.

Fibrinogen refers to acute phase proteins, and its plasma concentration increases with infection, inflammation, trauma and stress. Synthesis of fibrinogen stimulates hormones( insulin, progesterone), fatty acids and PDF.Nevertheless, the main stimulator of fibrinogen synthesis is the secretion of IL-6 by macrophages and monocytes in response to phagocytosis of PDF.The concentration of fibrinogen in the blood plasma is increased in smokers who have diabetes mellitus. As the concentration of fibrinogen increases, the risk of cardiovascular diseases increases. In women, the concentration of fibrinogen is higher than that of men, and their increase with age is more noticeable.

Table Reference values ​​for fibrinogen concentration in blood plasma

Table Reference values ​​for fibrinogen concentration in blood plasma

Increased fibrinogen concentration or its decrease is noted in the following conditions and diseases.■ Hypercoagulation at various stages of thrombosis, myocardial infarction, and also in the last months of pregnancy, after childbirth, after surgical operations.

■ Inflammatory processes, in particular pneumonia. In this connection, the determination of fibrinogen concentration in plasma is used in parallel with the determination of ESR to monitor the course of the inflammatory process.

■ Neoplastic processes, especially for lung cancer.

■ Light forms of hepatitis( the concentration of fibrinogen can be increased).Heavy liver damage( acute hepatitis, cirrhosis) is accompanied by a decrease in the concentration of fibrinogen.

■ Hereditary affibrinogenemia and hypofibrinogenemia, primary fibrinolysis( fibrinogen concentration reduced).

■ DIC syndrome in which changes in fibrinogen concentration depend on the form and stage of the process. In cases of chronic form of DIC-syndrome, as well as in the first stage of acute DIC-syndrome, the concentration of fibrinogen is increased. Later, there is a decrease in the concentration of fibrinogen, which indicates the transition of the process to the following( II and III) stages and is explained by its increased consumption. In the II stage of DVS-syndrome the concentration of fibrinogen decreases to 0.9-1.1 g / l, and in III it becomes less than 0.5 g / l, or it is not determined at all. When evaluating the results of studies, it is necessary to take into account not only the absolute, but also the relative decrease in the fibrinogen concentration in comparison with the initial, increased indices. The pronounced progressive decrease in the concentration of fibrinogen in the II-III stages of acute DIC syndrome is regarded as an unfavorable sign, while the improvement of the condition is accompanied by its increase.