Guidelines for laboratory diagnosis of factor XIII deficiency.

Factor XIII (FXIII) deficiency is an extremely rare hemorrhagic disorder with an approximate worldwide incidence of one per two million. With current tests, diagnosis of this disease can be made more precisely. However, factors such as the number of patients with FXIII deficiency (FXIIID), available diagnostic coagulation tests and the number of molecular studies have affected the diagnosis of FXIIID in different parts of the world. Various laboratory approaches can be used, including screening and diagnosis of the disorder in countries with a relatively high rate of FXIIID and recurrent mutation(s) with a simple polymerase chain reaction-restriction fragment length polymorphism analysis or polymerase chain reaction-sequencing for detection of one or a few specific mutations. In other countries, two different laboratory approaches can be used, depending on available coagulation tests. In less-equipped coagulation laboratories, the clot solubility test remains the only diagnostic test for FXIIID. Even in these countries, at least one referral laboratory should perform FXIII activity and, if possible, confirmation of FXIIID by molecular analysis. In countries with well equipped coagulation laboratories, FXIII activity should be used to screen suspected FXIIID patients; more specific tests such as molecular analysis should be used for confirmation. This study suggests a simple, reliable and flexible algorithm for early diagnosis of FXIIID, and may, with one-time diagnosis of FXIIID, reduce the rate of morbidity and mortality in patients with the disorder.