Evaluation of latex agglutination kits for detection of fibrin(ogen) degradation products and D-dimer in healthy horses and horses with severe colic.
BACKGROUND
Fibrin(ogen) degradation products (FDPs) and D-dimer are sensitive indicators of excessive fibrinolysis due to disseminated intravascular coagulation (DIC) in dogs. To the authors' knowledge, latex-agglutination-based plasma FDP and D-dimer assays have not been validated for use in horses.


OBJECTIVE
To determine: 1) sensitivity and specificity of latex agglutination serum and plasma FDP and D-dimer assays for diagnosis of DIC; and 2) their prognostic value in horses with severe colic.


METHODS
At hospital admission and 24 hours later, blood was collected from 30 healthy horses and 20 horses with severe colic. Horses fulfilling predefined laboratory criteria of DIC were enrolled, and their data were subcategorized by survival for analysis. Platelet counts were determined and coagulation panel testing was performed. Serum and plasma FDP concentrations were measured using separate latex agglutination kits. Plasma D-dimer concentration was measured using 3 latex agglutination kits and a card immunofiltration test. Test sensitivity and specificity results were determined for healthy horses and those with colic. Median test values were compared between colic survivors and nonsurvivors to evaluate the prognostic usefulness of all tests.


RESULTS
Performance characteristics varied among assays and kit suppliers. The FDP assays had low sensitivity (<40%), whereas the most accurate D-dimer kit had 50% sensitivity and 97% specificity. High D-dimer concentration was the third most common hemostatic abnormality in horses with colic. Median antithrombin (AT) activity was significantly lower and activated partial thromboplastin time (aPTT) was significantly longer in nonsurvivors than survivors.


CONCLUSIONS
Commercial latex-agglutination D-dimer assays might prove useful as adjunctive tests for the diagnosis of DIC in horses with severe colic; however FDP assays are invalid for this purpose. Low AT activity and prolonged aPTT at admission are associated with a poor prognosis in this patient population.
Stokol
Tracy
T
Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA. ts23@cornell.edu
Erb
Hollis N
HN
De Wilde
Lisa
L
Tornquist
Susan J
SJ
Brooks
Marjory
M
D000818:Animals; D001780:Blood Coagulation Tests / Q000379:methods / Q000662:veterinary; D003085:Colic / Q000097:blood / Q000175:diagnosis / Q000662:veterinary*; D004211:Disseminated Intravascular Coagulation / Q000097:blood / Q000175:diagnosis / Q000662:veterinary; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis* / Q000378:metabolism; D005342:Fibrinolysis; D006487:Hemostasis; D006734:Horse Diseases / Q000097:blood* / Q000175:diagnosis; D006736:Horses / Q000097:blood*; D007841:Latex Fixation Tests / Q000379:methods / Q000662:veterinary*; D010314:Partial Thromboplastin Time / Q000379:methods / Q000662:veterinary; D010976:Platelet Count / Q000379:methods / Q000662:veterinary; D011379:Prognosis; D011933:Reagent Kits, Diagnostic / Q000662:veterinary; D012680:Sensitivity and Specificity
D005338:Fibrin Fibrinogen Degradation Products; D011933:Reagent Kits, Diagnostic; C036309:fibrin fragment D