Factor XIII deficiency diagnosis: Challenges and tools.

Factor XIII deficiency (FXIIID) is a rare hereditary bleeding disorder arising from heterogeneous mutations, which can lead to life-threatening hemorrhage. The diagnosis of FXIIID is challenging due to normal standard coagulation assays requiring specific FXIII assays for diagnosis, which is especially difficult in developing countries. This report presents an overview of FXIIID diagnosis and laboratory methods and suggests an algorithm to improve diagnostic efficiency and prevent missed or delayed FXIIID diagnosis. Assays measuring FXIII activity: The currently available assays utilized to diagnose FXIIID, including an overview of their complexity, reliability, sensitivity, and specificity, as well as mutational analysis are reviewed. The use of a FXIII inhibitor assay is described. Diagnostic tools in FXIIID: Many laboratories are not equipped with quantitative FXIII activity assays, and if available, limitations in lower activity ranges are important to consider. Clot solubility tests are not standardized, have a low sensitivity, and are therefore not recommended as routine screening test; however, they are the first screening test in almost all coagulation laboratories in developing countries. To minimize the number of patients with undiagnosed FXIIID, test quality should be improved in less well-equipped laboratories. Common country-specific mutations may facilitate diagnosis through targeted genetic analysis in reference laboratories in suspected cases. However, genetic analysis may not be feasible in every country and may miss spontaneous mutations. Centralized FXIII activity measurements should also be considered. An algorithm for diagnosis of FXIIID including different approaches dependent upon laboratory capability is proposed.