D-dimer concentrations in healthy dogs and dogs with disseminated intravascular coagulation

OBJECTIVE: To determine sensitivity and specificity of assays of D-dimer concentrations in dogs with disseminated intravascular coagulation (DIC) and healthy dogs and to compare these results with those of serum and plasma fibrin-fibrinogen degradation product (FDP) assays. ANIMALS: 20 dogs with DIC and 30 healthy dogs. PROCEDURE: Semi-quantitative and quantitative D-dimer concentrations were determined by use of latex-agglutination and immunoturbidometry, respectively. Fibrin-fibrinogen degradation products were measured by use of latex-agglutination. A reference range for the immunoturbidometric D-dimer concentration assay was established; sensitivity and specificity of the assay were determined at 2 cutoff concentrations (0.30 microg/ml and 0.39 microg/ml). RESULTS: Reference range for the immunoturbidometric D-dimer concentration assay was 0.08 to 0.39 microg/ml; median concentrations were significantly higher in dogs with DIC than in healthy dogs. Latex-agglutination D-dimer and serum and plasma FDP assays had similar sensitivity (85 to 100%) and specificity (90 to 100%); the immunoturbidometric assay had lower specificity (77%) at the 0.30 microg/ml cutoff and lower sensitivity (65%) at the 0.39 microg/ml cutoff. Sensitivity or specificity of the latex-agglutination D-dimer assay was not significantly improved when interpreted in series or parallel with FDP assays. CONCLUSIONS AND CLINICAL RELEVANCE: Measurement of D-dimer concentrations by latex-agglutination appears to be a sensitive and specific ancillary test for DIC in dogs. Specificity of D-dimer concentrations in dogs with systemic disease other than DIC has not been determined, therefore FDP and D-dimer assays should be performed concurrently as supportive tests for the diagnosis of DIC in dogs.