| Description: |
Factor XIII serves to cross-link fibrin, resulting in mechanical and chemical stability of the clot. Patients with factor XIII deficiency have normal clotting times and platelet function tests. The basis of the factor XIII screen is that normally a clot is stable for 24 hours in 5M urea, while in factor XIII deficiency the clot is unstable over a time period of minutes. Clinically affected individuals have <1% factor XIII activity. Congenital deficiency is often manifested as umbilical stump bleeding; intracranial hemorrhage is also frequently reported. Acquired deficiency of factor XIII is most commonly due to inhibitors (autoantibodies). INH therapy has been associated with development of factor XIII inhibitors. The PT and PTT are normal in patients with factor XIII deficiency. |
