Factor XIII (fibrin stabilizing factor)

What Sample is needed for Factor XIII (fibrin stabilizing factor)?

• Plasma (Citrate) is needed, and it is stable for 2 hours at 4 °C only.

What is the Indication for Factor XIII (fibrin stabilizing factor)?

• To find the deficiency of factor XIII.

What is the history of fibrin stabilizing factor (XIII)?

1. This fibrin stabilizing factor (XIII) was discovered in 1944, and its role was confirmed in 1966.
2. It has a crucial role in stabilizing the fibrin clot in the last stage of clotting.

How will you define Factor XIII (Fibrin stabilizing factor)?

1. Factor XIII (Fibrin stabilizing factor) stabilizes a polymerized fibrin clot in the presence of calcium in the initial clot stage.
2. It is responsible for the cross-linking of the fibrin strands, which will strengthen and stabilize the final clot.
3. It does not circulate in the plasma.

Describe the Fibrin stabilizing factor (XIII) structure?

Fibrin stabilizing factor (Factor XIII) structure and activation

How will you discuss the Pathophysiology of the fibrin stabilizing factor (XIII)?

1. Factor XIII deficiency is congenital and inherited as an autosomal recessive trait with a severe coagulation defect.
   1. Clinically, the homozygous deficiency has moderate to severe hemorrhagic episodes.
2. Factor XIII is present in the plasma, platelets, monocytes, and macrophagic cells.

Factor XIII role in stabilizing the clot formation

What are the Functions of factor XIII?

1. Factor XIII cross-linked fibrin and other proteins.
2. It stabilizes the clot. Its >5% activity is required to form a normal clot.
3. The stabilized fibrin clot in factor XIII deficiency becomes insoluble in various substances like urea.
4. This factor helps in wound repair and healing.

Factor XIII’s role in stable clot formation

How will you describe deficiency of factor XIII (Fibrin stabilizing factor)?

1. Congenital deficiency:
   1. It is transmitted as an autosomal recessive trait.
   2. First, bleeding is noted in newborns.
   3. In later life, bleeding episodes are mild with severe trauma or surgery.
   4. Delayed bleeding after trauma.
   5. Poor wound healing.
   6. Inadequate scar formation.
   7. Bleeding is common after separating the umbilical cord in case of factor XIII deficiency.
2. A secondary deficiency:
   1. It may be seen in various conditions:
   2. Malignancies like AML.
   3. In liver diseases.
   4. Presence of circulating inhibitors.
   5. Associated with hypofibrinogenemia in obstetric complications.
   6. This type of deficiency is subclinical.

Factor XIII (Fibrin stabilizing factor) deficiency

What are the signs and symptoms of XIII (Fibrin stabilizing factor) deficiency?

1. Bleeding was first noted in newborns. Later on, bleeding episodes are mild except for severe trauma and surgery.
2. There is easy bruising and soft tissue bleeding, which may be due to trauma.
   1. There may be a severe bleeding tendency.
   2. The bleeding tendency may be like hemophilic patients; these patients may have hemarthrosis and deep tissue bleeding.
   3. This bleeding is characterized by the initial stoppage of bleeding followed by the recurrence of the bleeding after 36 hours or more after the initial trauma.
      1. This resulted from the fibrin clot dissolution that formed in the beginning and was not stabilized by factor XIII.
      2. Acquired partial deficiency has been reported with a few diseases like leukemia, DIC, and severe liver disease.
3. It may lead to spontaneous miscarriage in early pregnancy.
   1. There may be bleeding from the umbilical cord, which may be from 1 to 9 days of birth.
4. It may lead to CNS hemorrhage, which is quite common. This may be the first symptom.
   1. Patients with CNS hemorrhage may have headaches, vomiting, seizures, and focal neurologic defects.
5. Some of the females may have intra-abdominal bleeding during menses.
6. There will be bleeding into the joints (hemarthrosis).
7. There is poor wound healing.

What is the Normal Factor XIII (Fibrin stabilizing factor)?

1. Plasma concentration = 2.5 mg/dl.

Source 1

1. The test is negative with factor XIII above the minimal hemostatic level of 0.02 to 0.05 U/mL (x1000 = 20-50 U/L).
   1. OR 2%  to 5% (x0.01 = 0.02 to 0.05, fraction) of normal concentration.
   2. The clot will be stable for 24 hours with factor XIII above the hemostatic level.
   3. In the absence of factor XIII, the clot will dissolve, often within 2-3 hours or less.

How will you do Lab diagnose of factor XIII deficiency?

1. PT, APTT, fibrinogen, bleeding time, and platelet count are normal.
   1. All these parameters may be normal in congenital deficiency.
2. The clot is soluble in 5 Molar urea solution, which will not occur in a normal person.
3. A whole blood clot is qualitatively friable.

 How will you describe the Factor XIII screening test?

1. In factor XIII deficiency, coagulation tests are usually normal.
2. The other coagulation tests do not detect the deficiency of factor XIII.
3. The minimum level required for factor XIII is about 5%.
4. Principle of the test:
   1. Stabilization of the clot is dependent on factor XIII.
      1. The clot is soluble in 5 M urea.
   2. In the test after 24 hours, the presence of a formed clot indicates plasma factor XIII concentration greater than 1% to 2%.
   3. In the homozygous deficiency of factor XIII, the fibrin clot dissolves within one hour and indicates a deficiency of less than 1%.

How will you Treat factor XIII (Fibrin stabilizing factor) deficiency?

1. The following blood substitutes can be tried.
   1. Fresh frozen plasma.
   2. Cryoprecipitate.
   3. Factor XIII concentrate.
   4. Factor XIII recombinants.

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