Which findings on a qualitative screening test suggest factor XIII (FXIII) deficiency?

Updated: Aug 01, 2019
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Perumal Thiagarajan, MD  more...
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The next test performed is a qualitative screening test for severe FXIII deficiency that assesses clot solubility in 5M urea or 1% monochloroacetic acid. If the thrombin and Ca2+ -induced clot lyses within a few hours, severe FXIII deficiency is suggested provided fibrinogen levels are qualitatively and quantitatively within reference range. Excluding hypofibrinogenemia and dysfibrinogenemia is important, since these conditions cause false-positive results on the 5M urea solubility test. The thrombin-clottable fibrinogen test can be used to exclude hypofibrinogenemia and dysfibrinogenemia.

If the 5M urea solubility test demonstrates positive results, this finding should be confirmed by quantitating FXIII activity using a monodansylcadaverine or putrescine incorporation assay, which must be performed by laboratory personnel with expertise.

Thromboelastography (TEG) is an old method used to assess clotting and lysis of fresh whole blood, and it has been used as an early tool in the initial evaluation, and as a simple laboratory test, of the mechanical strength (effect of FXIII) of fibrin sealants. [97] However, TEG cannot supplant any of the qualitative or quantitative tests discussed in this section.

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