All you want to know about coagulation factors is here

Nomenclature of coagulation factors

For uniform naming, the World Health Organization is numbered with Roman numerals in the order in which they were discovered.
There are coagulation factors I , II , III , IV , V , VII , VIII , IX , X , XI , XIII , XIII , etc.
Factor XIII is Coagulation factors discovered later, after years of verification, are considered to have no decisive influence on coagulation function, and are no longer included in the number of coagulation factors
.
Factor VI is in fact the activated fifth factor, so the nomenclature of Factor VI has been dropped .

major coagulation factor

Factor l : fibrinogen factor II : thrombin factor factor III : tissue factor factor IV : calcium factor ( Ca2+ ) factor V : prothrombin, variable factor factor VII : transition accelerating factor precursor, prothrombin Prokinase, auxiliary thromboplastin factor VIII : anti-hemophilic globulin A ( AHG A ), anti-hemophilic factor A ( AHFA ), platelet cofactor I , hemophilic factor VIII or A factor IX : anti -hemophilic factor A (AHFA) Hemophilic globulin B ( AHG B ), antihemophilic factor B ( AHF B ), hemophilic factor IX or factor B















X : STUART ( -PROWER ) -F , autologous prothrombin C

factor XI : ROSENTHAL factor, antihemophilic globulin C

factor XII : HAGEMAN factor, surface factor factor XIII : fibrinostabilizing factor

coagulation factor

FITZGERALD factor

FLETCHER factor ( prokallikrein)

von-Willebrand- factor disqualified coagulation factor factor VI , prothrombin: actually activated fifth factor .
These factors work together to cause blood clotting .
Blood coagulation is a process in which coagulation factors are activated in a certain order, and finally fibrinogen is converted into fibrin.
It can be roughly divided into two stages, the activation of prothrombin and the formation of fibrin .

prothrombin activation

There are both endogenous and exogenous activation systems in the body
.
Endogenous means that the cardiovascular intima is damaged, or the blood flow out of the body activates factor XII through contact with abnormal surfaces, which is initiated by the activation of factor XII .
When the blood vessel is damaged and the collagen fibers under the intima are exposed, XII can be activated to become XIIa , and then XI can be activated to become XIa .
XIa activates IXa in the presence of Ca2+ , and IXa forms a complex with activated VIIIa , PF3 and Ca2+ to further activate X.
The factors involved in the above process of coagulation are all present in the blood plasma, so it is named the intrinsic coagulation pathway .
Due to the existence of factor VIIIa , the rate of activation of X by IXa can be accelerated by 200,000 times.
Therefore, the lack of factor VIII can hinder the intrinsic coagulation pathway, and slight damage can cause continuous bleeding.
Clinically, it is called " hemophilia A ".





.

Exogenous is initiated by contact of damaged tissue-exposed factor III with blood
.
When the tissue damaged blood vessels rupture, the exposed factor III forms a complex with Ca2+ and VII in the plasma to activate factor X.
Because the factor III that initiates this process comes from extravascular tissues, it is called the extrinsic coagulation pathway .

fibrin formation

Under the action of thrombin, fibrinogen dissolved in plasma is converted into fibrin monomer, and at the same time, thrombin activates XIII to XIIIa , which connects fibrin monomers to each other to form water-insoluble fibrin multimers.
They are intertwined with each other to form a network of blood cells to form blood clots and complete the blood coagulation process.
Blood coagulation is a series of enzymatic biochemical reaction processes.
There are many positive feedback effects.
Coagulation and hemostasis effect occurs in a relatively short period of time
.

Intrinsic and extrinsic coagulation pathways can activate each other
.
VIIa , VIa , IXa in endogenous coagulation are the main activators of exogenous coagulation factor VII ; factor IXa in exogenous coagulation can activate XII , thus partially replacing the functions of XIa and Xa .
The cross-activation of internal and external coagulation source pathways shows the flexible and flexible coagulation mechanism of the body .

common pathway

From factor X activation to fibrin formation, it is a common coagulation pathway of endogenous and exogenous coagulation
.

① Thromboplastin formation: that is, Xa , factor V , PF3 and calcium ions form a complex, namely thromboplastin, also known as prothrombinase
.

②Thrombin formation: Under the action of prothrombinase, prothrombin is converted into thrombin
.

③ Fibrin formation: Fibrin contains three pairs of polypeptide chains, of which A and B contain many acidic amino acids, so they have more negative charges.
Thrombin hydrolyzes the more negatively charged fibrin peptides A and B and removes them.
Converted into fibrin monomers, soluble in urea or sodium bromide, and soluble fibrin; at the same time, thrombin activates the factor, which cross-links soluble fibrin to form insoluble stable fibrin, thereby Form blood clots
.
So far the coagulation process is complete
.

related diseases caused by factor deficiency

Hereditary coagulation factor deficiency disease: It is characterized by frequent bleeding symptoms since childhood, with a family history of inheritance.
Except for hemophilia A and B, which are sex chromosomal recessive inheritance, they are generally autosomal recessive inheritance, and can be both male and female.
Sick, often consanguineous marriage history
.
The diseases in this group are all single coagulation factor deficiency, of which factor VIII deficiency (hemophilia A) is the most common, and all other factors can be deficient except for Ⅲ and Ⅳ .

Acquired coagulation factor deficiency diseases: common such as vitamin K deficiency, for the lack of factors II , VII , IX , X , and severe liver disease
.
Diagnosis is by examining coagulation patterns and correcting tests
.
Treatment with fresh plasma or cryoprecipitate is effective, and for acquired patients, the primary disease should be treated
.

Prothrombin deficiency: more common in neonatal hemorrhage and severe liver disease
.
1 to 5 days after birth, the lack of prothrombin due to lack of intestinal bacteria and inability to synthesize vitamin K ; in patients with complete biliary atresia, the lack of bile affects the absorption of fat-soluble vitamin K or digestive disorders.
Patients with poor absorption of vitamin K cannot synthesize sufficient prothrombin .
Acute infectious hepatitis, toxic hepatitis, acute yellow liver atrophy, liver cirrhosis and other severe liver diseases can occur prothrombin deficiency and often combined with factor V , XII , X deficiency (called prothrombin complex deficiency) .
Patients with severe liver disease may also experience severe bleeding due to increased anticoagulant factors such as heparin .

Factor XII deficiency: The disease, also known as Hagerman's factor deficiency, is familial and can be affected by both men and women
.
Factor XII is inactive in plasma, and when vascular damage or endothelium is damaged, it is activated by contact with subendothelial collagen, starting the endogenous coagulation system
.
The patient has no bleeding tendency on weekdays, and only has mild bleeding after surgery or trauma, because when factor XII is deficient, factor XI can replace factor XII as a triggering factor
.

Factor V deficiency: Also known as parahemophilia, or Ovren's disease
.
There are two types of congenital or acquired
.
Acquired in severe liver disease, leukemia , sepsis, etc.
, both men and women can be affected
.

Factor VII deficiency: there are two types of congenital or acquired
.
Patients with congenital factor VII deficiency have bleeding manifestations in neonates and early childhood
.

Factor X deficiency: there are two types of congenital and acquired, both men and women can be affected
.
Factor X is synthesized in the liver and requires vitamin K as a coenzyme
.
This factor is poorly synthesized in patients with vitamin K deficiency and severe liver disease
.
Dicoumarin excess, amyloidosis and disseminated intravascular coagulation in patients with this factor is often reduced
.

Factor XIII deficiency: XIII is a transamidase, and in soluble fibrin polymers, XIII covalently links fibrin monomers together
.
Covalently linked multimers are insoluble fibrin multimers with stable properties
.
Acquired factor XIII deficiency is seen in lupus erythematosus, autoimmune hemolytic anemia, uremia, leukemia, malignant lymphoma , multiple myeloma, cirrhosis, and fulminant hepatitis
.
Long-term use of isoniazid can produce anti-factor XIII antibodies, which can inactivate or neutralize factor XIII , affecting the stability of the clot, and the patient has a tendency to bleeding
.

The significance of factor activity measurement

reduce: 

1.
Factor VIII : C decreased, seen in hemophilia A , von Willebrand disease, disseminated intravascular coagulation, etc.
;

2.
Factor IX : C decreased, seen in hemophilia C , liver disease, vitamin K deficiency, disseminated intravascular coagulation, oral anticoagulants, etc.
;

3.
Factor XI : C decreased, which can be seen in congenital factor XI deficiency, vitamin K deficiency, disseminated intravascular coagulation, etc.
; 

4.
Factor XII : C decreased, which can be seen in congenital factor XII deficiency, disseminated intravascular coagulation, liver disease, etc.
;

5.
Factor II : C , factor V : C , factor VII : C , factor X : C decrease, seen in congenital coagulation factor deficiency or acquired coagulation factor decrease, such as liver disease, vitamin K deficiency, disseminated intravascular coagulation, Oral anticoagulants and people with anticoagulant substances in their blood
.

Raised: 

Found in blood hypercoagulable state and thrombotic diseases, such as deep vein thrombosis, pulmonary embolism, nephrotic syndrome, pregnancy-induced hypertension syndrome and malignant tumors
.
 

Note: People who take aspirin for a long time are not suitable for coagulation factor activity determination
.