Early Reading | Understanding Coagulation Factor L

Coagulation factor l is fibrinogen, (Fib or Fbg) fibrinogen is a macromolecular sugar containing 2964 amino acids Protein, with a relative molecular mass of 340 × 10^3, fibrinogen is composed of three pairs of different polypeptide chains, α, β, and γ, and the polypeptide chains are connected by disulfide bonds. Under the action of thrombin, the α chain and the β chain release A peptide and B peptide, respectively, to generate fibrin monomers. Fibrinogen is synthesized by the liver and thus reflects hepatic synthetic function.

As coagulation pathway I factor, Fg is converted into reticulofibrinHemostatic thrombus and platelets form together firmly

Fibrinogen is an acute phase protein with coagulation function synthesized by the liver and is a key protein directly involved in the coagulation process. It can cause imbalance of coagulation and fibrinolysis systems in the body.

Fibrinogen and Disease

1. Human fibrinogen and liver disease

Human fibrinogen is synthesized in the liver, mainly distributed in plasma, but also in platelets and megakaryocytes. The normal plasma concentration is 1.5-3.5g/L, so when the liver is severely damaged, the fibrinogen synthesis function of the liver is impaired, and the plasma fibrinogen concentration decreases. Fibrinogen is a plasma glycoprotein synthesized by the liver. It can participate in the formation and development of thrombus and coronary arteries. It is an indicator reflecting the state of thrombus and one of the independent predictors of acute coronary events. Elevated fibrinogen indicates a decrease in the body’s fibrinolytic activity and promotes thrombosis.

2. Human fibrinogen and nephrotic syndrome (NS)

The changes of coagulation factors in patients with NS, with the most obvious increase in the level of fibrinogen. Fibrinogen levels can increase up to 10 g/L as a result of increased synthesis proportional to the amount lost in the urine, but the catabolism rate of fibrinogen is normal. Fibrinogen and cholesterol levels were significantly correlated in NS patients, and both were negatively correlated with serum albumin levels.

3. Human fibrinogen and atherosclerosis

Human fibrinogen and cellulose are closely related to the formation of atherosclerosis . It is known that the mechanism of fibrinolysis is affected by many factors, such as smoking, diabetes, especially high serum triglycerides can cause the increase of plasma plasminogen activator inhibitor, thereby reducing the synthesis of plasminogen. The blood viscosity is relatively high, which is conducive to the formation of cellulose.

Fibrinogen is an acute phase protein, which enters the arterial wall as coagulation factor I from the blood, and is converted into fibrin monomer by thrombin. Combined with fibrin, it can directly destroy endothelial cells to adhere to the surface of erythrocytes, increase the incidence of arterial thrombosis, and promote the rapid progression of atherosclerosis. In addition, plasma fibrinogen can be deposited in the blood vessel wall and accelerate atherosclerosis. It has been found that the amount of fibrin aggregates in atherosclerotic plaques increases the content of fibrinogen in the disease group, and all have increased blood viscosity. Characteristics of atherosclerosis and even obstruction.

4. Human fibrinogen and cardiovascular and cerebrovascular diseases

The study on thrombosis in acute ischemic syndrome showed that plasma fibrinogen level was an independent risk factor, Plasma fibrinogen levels were higher in patients with coronary occlusive disease, and the extent of myocardial infarction was also closely related to the degree of fibrinogen increase. Patients with unstable angina pectoris often have elevated plasma fibrinogen levels before myocardial infarction. In the course of myocardial infarction, reinfarction mostly occurred in patients with fibrinogen level exceeding 7g/L.

5. Human fibrinogen and hemorheology

found that fibrinogen was significantly positively correlated with whole blood viscosity, plasma viscosity, erythrocyte sedimentation rate and platelet aggregation. Prompt plasma fibrinogen content increased, can increase blood viscosity. The aggregation of erythrocytes is increased, and the aggregation of platelets is increased, so that the blood is in a hypercoagulable state and promotes thrombosis. Plasma fibrinogen levels are elevated because of their large molecular weight. High concentration, but also has polymerization, is an important factor to increase blood viscosity in addition to red blood cells; therefore. Plasma fibrinogen content is of great significance in judging the occurrence and development of diseases.

6. Human fibrinogen and other factors

There are many other factors that affect the level of fibrinogen, such as genetic predisposition, increasing age, hyperlipidemia, smoking, essential hypertension, obesity, oral contraceptives and pregnancy are all risk factors for elevated plasma fibrinogen.

Fibrinogen meaning

Elevated Fbg: (more than 4g/L) seen in diabetes and diabetic acidosis, arterial thromboembolism (acute myocardial infarction) , acute infectious diseases, connective tissue diseases, acute nephritis and uremia, after radiation therapy, burns, myeloma, shock, after major surgery in the elderly, third trimester and pregnancy-induced hypertension, mild hepatitis, sepsis, acute infection and malignant tumor Wait.

Fbg reduction: (less than 2g/L) primary fibrinogen reduction or structural abnormalities. Secondary fibrinogen reduction: advanced DIC, severe hepatitis and cirrhosis, etc., also seen in anti-fibrillar drug therapy (such as antithrombotic enzymes, defibrase) and thrombolytic therapy [UK, tissue plasminogen activator ( t-PA)].

How to supplement for reduced fibrinogen


Especially fresh frozen plasma contains various coagulation factors, but multiple studies have shown that the efficacy of infusion varies, the level of fibrinogen supplementation is not stable, and there may be In the case of blood transfusion overload, it is not the best foreign aid. Usual dosage: 10ml/kg-15ml/kg.


rich in fibrinogen , coagulation factor VIII, XIII, vWF factor and fibronectin. Each unit of cryoprecipitate contains 200 to 250 mg of fibrinogen. The usual clinical dose is 0.2-0.3U/kg. However, cryoprecipitate should not be used as a first-choice external aid when a single coagulation factor preparation is available.

Fibrinogen Concentrate:

reduces The infusion of allogeneic blood products ensures the infusion efficiency and reduces adverse reactions, and should be the best foreign aid. The main indications of domestic marketed products include: 1. Congenital fibrinogen reduction or deficiency. 2. Acquired fibrinogenosis: severe liver damage; cirrhosis; DIC; postpartum hemorrhage and coagulation disorders caused by fibrinogen deficiency caused by major surgery, trauma or internal bleeding.

Disclaimer: This article is from the emergency time, the author of sulfur vapor , is only for learning and communication, and the copyright belongs to the original author.

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