Factor XIII deficiency occurs exceedingly rarely, causing a severe bleeding tendency.

Deficiency of Factor XIII leads to defective cross-linking of fibrin and vulnerability to late re-bleeds when the primary hemostatic plug is overwhelmed.

[2][3] Bleeding manifestation with normal PT, aPTT, TT, BT, and CT is suspected as factor XIII Deficiency.

[citation needed] Fresh frozen plasma and cryoprecipitate are the mainstay of therapy for Factor XIII deficiency, but carry risk related to transfusion.

[2] rFXIII acts by inhibiting fibrinolysis factors which enzymatically cleave the fibrin matrix, leading to the ultimate formation of clots.