The following post was written several years ago. Although more recent developments have changed the field of clinical laboratory science since the original posting, the information contained was deemed to be of historical interest.

A toddler has a history of severe bleeding with minor trauma. Child abuse was excluded by evaluation of the family. The initial evaluation includes normal PT, PTT, thrombin time, platelet count and PFA-100. What should you next consider and how can the diagnosis be made?

Answer: Factor XIII deficiency (fibrin-stabilizing factor). The possible diagnostic tests include the 5M urea solubility test, the euglobulin lysis test or quantitation of the A and B subunits of factor XIII (the preferred measurement if the factor XIIIA(2)B(2) antigen screen is abnormally low). Recall that factor XIII is not measured in the PT, PTT or thrombin time tests.

  1. Schroeder V, Durrer D, Meili E, Schubiger G, Kohler HP. Congenital factor XIII deficiency in Switzerland: from the worldwide first case in 1960 to its molecular characterization in 2005. Swiss Med Wkly. 2007 May 19;137(19-20):272-8.
  2. Hsieh L, Nugent D. Factor XIII deficiency. Haemophilia. 2008 Nov;14(6):1190-200.
  3. Karimi M, Bereczky Z, Cohan N, Muszbek L. Factor XIII Deficiency. Semin Thromb Hemost. 2009 Jun;35(4):426-38.