From the Research
Factor XIII deficiency does not affect PT (prothrombin time) or PTT (partial thromboplastin time) test results, which typically remain normal in these patients. This is because Factor XIII functions after initial clot formation, stabilizing the fibrin clot by creating cross-links between fibrin molecules. PT and PTT tests only measure the time to initial clot formation, which occurs before Factor XIII's activity in the coagulation cascade. Therefore, standard coagulation screening tests will miss this deficiency. Specific Factor XIII activity assays are required for diagnosis, as noted in studies such as 1 and 2.
Key Points to Consider
- Factor XIII plays a crucial role in clot stabilization by cross-linking fibrin monomers, as discussed in 3 and 4.
- Patients with Factor XIII deficiency may present with delayed bleeding after trauma or surgery, poor wound healing, and recurrent miscarriages in women, despite having normal PT and PTT values, as mentioned in 5 and 2.
- The disconnect between normal screening tests and significant bleeding symptoms is a key diagnostic clue that should prompt specific Factor XIII testing.
- Treatment involves Factor XIII concentrate replacement to prevent or treat bleeding episodes, as outlined in 1 and 2.
Diagnostic Approach
- Specific Factor XIII activity assays are necessary for diagnosis, as standard coagulation tests like PT and PTT are not affected by Factor XIII deficiency.
- A study from 5 highlights the importance of understanding the mechanisms of thrombin generation and fibrin polymerization in the context of Factor XIII deficiency.
Management
- Factor XIII concentrate replacement is the mainstay of treatment for preventing or treating bleeding episodes in patients with Factor XIII deficiency, as discussed in 1, 2, and 4.
- The choice of replacement therapy, such as plasma-derived FXIII or recombinant FXIII, depends on various factors, including the severity of the deficiency and the patient's specific needs.