Comparison of quantitative immunoturbidimetric and semiquantitative latex-agglutination assays for D-dimer measurement in canine plasma.
BACKGROUND
D-dimer measurement in dogs is considered the most reliable test for detecting disseminated intravascular coagulation or thromboembolism.


OBJECTIVE
The purposes of this study were to compare 2 D-dimer assays, a quantitative immunoturbidimetric and a semiquantitative latex agglutination assay, and to assess the effect of hemolysis and storage conditions on D-dimer concentration using the quantitative assay.


METHODS
The immunoturbidimetric assay was validated using canine citrated plasma samples containing different concentrations of D-dimer. The effect of storage at various temperatures and times was assessed. Hemolysis was produced by adding lysed RBCs to the samples for a final hemoglobin concentration of 0.35 g/dL.


RESULTS
For clinically relevant values (>250 microg/L), intra-assay and interassay coefficients of variation were 6.8% and 7.2%. The assay was linear (r(2)=1.00), and the tests had good agreement (kappa=0.685, P<.001). Storage at 4 degrees C and -20 degrees C and hemolysis had no significant effect on D-dimer concentrations. In hemolyzed samples stored at room temperature for > or =48 hours, fine clots were noted and often resulted in falsely increased D-dimer concentrations.


CONCLUSIONS
Our findings suggest that the immunoturbidimetric assay validated in this study is reliable and accurate for the measurement of D-dimer in canine plasma. Samples can be stored for up to 1 month at -20 degrees C and moderate hemolysis does not significantly affect the D-dimer concentration in frozen or refrigerated samples.
Boutet
Philippe
P
Department of Veterinary Medicine, University of Cambridge, Cambridge, UK. phil.boutet@gmail.com
Heath
Fred
F
Archer
Joy
J
Villiers
Elizabeth
E
D000818:Animals; D004285:Dogs / Q000097:blood*; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D007841:Latex Fixation Tests / Q000662:veterinary*; D009391:Nephelometry and Turbidimetry / Q000379:methods / Q000662:veterinary*; D015203:Reproducibility of Results
D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D