Comparison of a direct latex-agglutination technic with the tanned red cell hemagglutination inhibition immunoassay (TRCHII) for semiquantitation of fibrinogen/fibrin degradation products.

A new latex-agglutination kit for rapid screening for fibrinogen/fibrin degradation products (FDP/fdp) has been compared with a standard tanned red cell hemagglutination inhibition immunoassay (TRCHII). The latex-agglutination test results agreed with the TRCHII results for 489 of 588 samples (83%). FDP/fdp values were elevated by the latex-agglutination kit when normal by the TRCHII for 79 (13%) samples, and the reverse was true for 20 (3%) samples. Serial dilution of serum sample allowed reliable semiquantitation of FDP/fdp levels compared with TRCHII results (r=less than .001). The latex-agglutination test gave FDP/fdp values of larger than or equal to 10 mug. per ml. for sera from 11 of 13 patients who had acute pulmonary embolism and for only one of 24 normal control samples. The direct latex-agglutination kit for FDP/fdp appears to have appropriate sensitivity to serve as a screening test for acute pulmonary embolism in patients not receiving heparin therapy.