Factor XIII (fibrin stabilizing factor)
Sample
- Plasma (Citrate) is needed and it is stable for 2 hours at 4 °C only.
Indication
- To find the deficiency of factor XIII.
Pathophysiology
- Factor XIII deficiency is congenital and inherited as an autosomal recessive trait.
- Clinically the homozygous deficiency has moderate to severe hemorrhagic episodes.
- Factor XIII is present in the plasma, platelets, monocytes, and macrophagic cells.
- Factor XIII has molecular weight 320.000 daltons circulates with fibrinogen.
- It consists of two subunits α2 – unit and β2 – unit chains.
- Factor XIII is also present in the above cell precursors in the bone marrow.
- Factor XIII has a long half of 5 to 9 days.
- Factor XIII cross-link fibrin and other proteins, and it stabilizes the clot.
- This factor helps in wound repair and healing.
- Congenital deficiency of factor XIII is rare, it causes:
- Delayed bleeding after trauma.
- Poor wound healing.
- Inadequate scar formation.
- Bleeding is common after the separation of the umbilical cord in case of factor XIII deficiency.
- In factor XIII deficiency, coagulation tests are usually normal.
Signs and symptoms of XIII deficiency:
- There is easy bruising and soft tissue bleeding which may be due to trauma.
- There may be a severe bleeding tendency.
- The bleeding tendency may be like hemophilic patients, these patients may have hemarthrosis and deep tissue bleeding.
- This bleeding is characterized by the initial stoppage of bleeding followed by the recurrence of the bleeding after the 36 hours or more after the initial trauma.
- This result from the dissolution of the fibrin clot that formed in the beginning and was not stabilized by the factor XIII.
- Acquired partial deficiency has been reported with few diseases like leukemia, DIC, and severe liver disease.
- There is a possibility of spontaneous miscarriage in early pregnancy.
- There may be bleeding from the umbilical cord which may be from 1 to 9 days of birth.
- There may be CNS hemorrhage which is quite common. This may be the first symptom.
- The patient with CNS hemorrhage may have a headache, vomiting, seizures, and focal neurologic defects.
- These patients may have intra-abdominal bleeding during menses.
- There will be bleeding into the joints (hemarthrosis).
- There is poor wound healing.
Lab diagnosis:
- PT, APTT, fibrinogen, bleeding time, and platelet count are normal.
- The clot is soluble in 5 Molar urea solution.
Normal
- Plasma concentration = 2.5 mg/dl.
Source 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).
- OR 2 to 5% (x0.01 = 0.02 to 0.05, fraction) of normal concentration.
- With factor XIII above the hemostatic level, the clot will be stable for 24 hours.
- In the absence of factor XIII, the clot will dissolve, often within 2-3 hours or less.
Factor XIII screening test:
- The deficiency of factor XIII is not detected by the other coagulation tests.
- The minimum level required for factor XIII is about 5%.
- Principle of the test:
- Stabilization of the clot is dependant on factor XIII.
- The clot is soluble in 5 M urea.
- In the test after 24 hours, the presence of a formed clot is indicating plasma factor XIII concentration greater than 1 to 2%.
- In the homozygous deficiency of factor XIII fibrin clot dissolve within one hour and indicates a deficiency of less than 1%.
- Stabilization of the clot is dependant on factor XIII.
Treatment
- The following blood substitutes can be tried.
- Fresh frozen plasma.
- Cryoprecipitate.
- Factor XIII concentrate.
- Factor XIII recombinants.