Latex agglutination-inhibition test for screening blood-clotting factor XIII in human plasma.

For the assay of blood-clotting Factor XIII (Fibrin-Stabilizing Factor, FSF), the antibody-neutralization test (Bohn and Haupt, 1968), the monodancylcadaverine incorporation test (Lorand et al., 1969; Nishimura et al., 1975) and the Laurell method are tried in our country (Hidano et al., 1975). None of them, however, could be applied to the clinical screening for Factor XIII-deficient cases; the development of a simple and rapid test procedure has been awaited for. We found that Factor XIII contained by the concentrate prepared by the Behring Institut was adsorbed to latex particles, which, then, were specifically agglutinated by rabbit anti-human Factor XIII antibody also supplied by the Behring Institut. When normal human plasma was added to the antibody prior to mixing the antibody with the antigen-coated latex particles, agglutination was no longer observed, indicating that the antibody had been consumed by its binding to the Factor XIII present in normal human plasma. For excluding any reaction attributable to subunit S, which is said to be still present in human serum after clotting had taken place and also in Factor XIII-deffcient plasma