Factor XIII Assays

Factor XIII (FXIII) deficiency is a rare cause of bleeding and pregnancy loss that is easily treated with plasma products. Reliable assays for FXIII are necessary not only for the diagnosis of deficiency state but also to guide prophylaxis and replacement therapy in patients during times of increased risk. Diagnostic tests for FXIII activity whilst not technically demanding have a number of pitfalls including limited sensitivity and overestimation of activity at the lower end. Despite these shortcomings the performance of these assays is adequate for the diagnosis and management of the majority of patients with clinically significant deficiency.