Clinical evaluation of a test for plasma fibrin/fibrinogen degradation products (FDP) based on monoclonal anti-FDP antibody technology: an application for the scoring system of the disseminated intravascular coagulation (DIC) diagnostic criteria

Fibrin/fibrinogen degradation products(FDP) have been measured using serum samples which were specially prepared for the FDP test because of the usage of anti-human fibrinogen antibody for the assay. Since diagnostic criteria for DIC were established by the study group on thrombosis and hemostasis which is supported by the Japanese Ministry of Health and Welfare(JMHW), serum FDP assay have been used as standard methods to diagnose DIC in Japan. Recently, a reagent using an anti-human FDP monoclonal antibody was developed and this has enabled the use of plasma samples for FDP measurement. The comparability, especially of the DIC score, of a new assay, Latex test BL-2 P-FDP, using plasma samples with a conventional assay for serum was investigated. Two sets of DIC scores based on data from the two tests were compared and the correlation was high with 97.5% of the patients being diagnosed with the same DIC status. In four disease groups--DIC, thrombosis, leukemia and solid cancer--high comparability between the two tests was also shown and no significant difference was observed in the correlation coefficient and the slope coefficient between serum and plasma samples. To conclude, it is suggested that "Latex test BL-2 P-FDP" is applicable to the diagnostic criteria for DIC from JMHW without any difficulty.     

Evaluation of two new assays for determination of serum fibrinogen/fibrin degradation products

Two new commercial assays for the detection of degradation products of fibrinogen/fibrin (FDP) were evaluated against two standard procedures. The first, a new hemagglutination inhibition (HAI) assay using glutaraldehyde-treated cells, was compared with the tanned red cell hemagglutination inhibition immunoassay (TRCHII). Analysis of 43 samples from patients with a variety of bleeding disorders and thrombotic conditions showed a high degree of correlation between methods (r = 0.934). The second new assay, a rapid slide test using antibody-coated latex particles, was compared with results obtained by electroimmunoassay. There were no significant differences in the results as assessed by two statistical parameters. It was concluded that both new tests are useful for routine use in clinical laboratories.     

Differentiation between fibrin degradation products and fibrinogen degradation products by using newly developed ELISAs

We should distinguish fibrin degradation products (FbDP) from fibrinogen degradation products (FgDP) in order to analyze fibrinolysis in vivo. We analyzed some disorders associated with hyperfibrinolytic states using ELISA for FbDP, FgDP and total fibrin (ogen) degradation products (TDP) (ORGANON TEKNIKA). Each ELISA was useful in terms of reproducibility and dilution linearity of plasma samples. There was no cross-reaction between FbDP and FgDP. The FgDP/FbDP ratio in normal individuals was 1.65. In patients with DIC, it was 0.43, with FgDP level being increased. These results suggest that fibrinolysis is enhanced in patients with DIC, but it is accompanied by fibrinogenolysis. On the other hand, the FgDP/FbDP ratio in patients given urokinase (UK) was 2.88. This suggests that fibrinogenolysis is enhanced in them. In our study, the FgDP/FbDP ratio increased as DIC improved. Thus, we can regard this as an index of therapeutic effects in patients with DIC. We conclude that these three ELISA are useful in analyzing disorders associated with hyperfibrinolytic states.     

The detection of fibrinogen/fibrin degradation products by means of a new antibody-coated latex particle

A rapid slide test for the detection of degradation products of fibrinogen/fibrin (FDP) using a new antibody-coated latex particle is described. The latex particle has been specifically coated with antibody to fragments D and E. The latex agglutination test (Thrombo-Wellcotest) has been compared with the tanned red cell haemagglutination inhibition immunoassay (TRCHII) in 143 patients with a variety of clinical conditions. There is a high degree of agreement between the methods with a coefficient of correlation of 0.83. The method provides a rapid, simple screening test for fibrin degradation products.     

Fibrinogen and fibrinogen/fibrin degradation products in the urine of rabbits infected with Trypanosoma (Trypanozoon) brucei

Summary Studies have been carried out on the urine of rabbits infected with Trypanosoma (Trypanozoon) brucei to determine whether fibrinogen or fibrinogen/fibrin degradation products (FDP) could be detected. No fibrinogen was found but during the last two weeks of this 7-week infection low levels of FDP were present in the urine which did not exceed 5 g/ml. Rabbit urine was shown to contain a potent proteolytic enzyme capable of breaking down rabbit fibrinogen and both early and late FDP were present in the cleavage products. No deposits of fibrin were detected in the kidney, but casts were present in the urine suggesting renal damage. The most likely explanation of the urinary FDP is that either an increase in the glomerular permeability occurs allowing filtration of plasma FDP or a local fibrinogenolysis in the kidney tubules.     

Serum fibrin/fibrinogen degradation products as a prognostic index in acute myocardial infarction.

A study of the prognostic value of serum fibrin/fibrinogen degradation products (FDP) in 137 consecutive patients with acute myocardial infarction showed a positive correlation between high FDP levels and poor prognosis. Both the frequency of complications and the mortality were related to increased levels of FDP, the highest of which were found between the fourth and eighth days after infarction.     

Analysis of cross-linked fibrin and fibrinogen degradation products with SDS-PAGE and immunoblot

SDS-PAGE and immunoblot technique with anti-FDP-D, -FDP-E, -fibrinogen antibody or anti-FDP-DD monoclonal antibody were applied to analyze FDP fragments prepared from cross-linked fibrin and fibrinogen with plasmic digestion in vitro. FDP fragments of DY(260K), DD(187K), X(245K), Y(166K), D(77K, 97K), E1(58K), E2(46K) and E3(40K) were identified from data of molecular weight and reactivity to four antibodies referred to reports of other investigators. Serum FDP fragments from five DIC suspected patients were analyzed by the same methods. In two patients' sera, DD fragment was a main component, and in the other three patients' sera, D fragment was a main fraction. Proportions of high molecular weight fragments of FDP were considerably different in patients' sera. Appearance of D fragment in our cases was considered to be derived from unstable fibrin (fibrin monomer and dimer) rather than from fibrinogen. Molecular weight of DD fragments from patients' sera had heterogeneity (160 approximately 180K), and the values were different from that (187K) prepared from cross-linked fibrin. In conclusion, SDS-PAGE and immunoblot analysis of serum fragments of FDP will be an useful technique to investigate the clinical and pathological condition of DIC.     

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.     

Rapid detection of cross-linked fibrin degradation products in plasma using monoclonal antibody-coated latex particles

Conformational and structural changes on conversion of fibrinogen to fibrin and its cross-linking by Factor XIIIa lead to the development of new antigenic determinants that permit differentiation between their plasminolytic cleavage products. A monoclonal antibody (DD-3B6/22) that is specific for cross-linked fibrin derivatives containing the D dimer configuration has been used in developing a latex agglutination procedure that can detect fibrin degradation products in either plasma or serum. Fibrinogen or its degradation products do not cross-react with this antibody. Results were calibrated with an enzyme immunoassay, which used a purified D dimer standard. Plasmas from 40 normal subjects, all having D dimer levels below 250 ng/mL measured by enzyme immunoassay, were all negative by latex assay. In contrast, positive latex agglutination titers were obtained with 87 of 88 patients with demonstrated deep venous thrombosis, pulmonary embolism, or disseminated intravascular coagulation. Compared to enzyme immunoassay, latex agglutination assay is less sensitive, but this latex procedure provides a rapid and less elaborate test for elevated levels of cross-linked fibrin degradation products in patients with thrombosis. Plasma assays for fibrin degradation products are preferable to those using serum.