In a presurgical work-up, which factor deficiency is suggested by normal platelet count and slightly prolonged PT, PTT, and TT with poor clot formation?

The scenario describes a presurgical work-up with a normal platelet count and slightly prolonged prothrombin time (PT), activated partial thromboplastin time (PTT), and thrombin time (TT), along with poor clot formation. The key to understanding this situation lies in recognizing how various factors affect coagulation and fibrin formation.

In this case, factor XIII deficiency is suggested. Factor XIII is crucial for cross-linking fibrin, which stabilizes the clot. Although the initial coagulation tests may be slightly prolonged, they often do not clearly indicate a factor XIII deficiency, especially since factor XIII is not included in routine PT and PTT tests. However, its deficiency leads to poor clot formation, demonstrated by the clinical finding of a clot that is fragile and easily lysed, resulting in ineffective hemostasis despite normal platelet counts.

This contrasts with the other factors listed. For instance, a deficiency of fibrinogen typically results in a significantly prolonged TT, along with potential issues in PT and PTT, as fibrinogen is essential in forming the fibrin mesh that forms the core of a stable clot. Similarly, prothrombin deficiency can lead to a significantly prolonged PT and PTT as well, as prothrombin plays