Overview

• Specific marker for activation of coagulation and fibrinolysis.
• D-dimers are a more specific form of fibrin degradation products Fibrin degradation products.
• Formed by the action of plasmin on cross-linked fibrin, hence not affected by lysis of fibrinogen.
• Negative D-dimers excludes DIC in dogs with a confidence level of 95%.
• Moderately sensitive (~90%) but non-specific for thrombosis in dogs with mild elevations.
• Large elevations are more specific but less sensitive in dogs.
• Neither sensitive nor specific in cats.

Sampling

Tests

Methodologies

• Semi-quantitative latex agglutination tests and a point-of care immunometric test have been validated for use in dogs.
• Quantitative immunoturbidimetric assays are available through reference laboratories.
• Latex agglutination and immunoturbidometric assays have been reported in cats but their utility and validity is less clear.

Availability

• Widely available through reference laboratories with some semi-quantitative point-of-care assays also available.

Validity

Sensitivity

• Elevations in D-dimers above the reference range are reported to be 80-90% sensitive for the detection of thrombosis or DIC Disseminated intravascular coagulation in dogs.
• The sensitivity of D-dimer elevations for detecting DIC in cats is reported to be 67% or less.

Specificity

• Mild elevations of D-dimers are non-specific in any species when compared to sick controls but good when compared to a healthy control population.
• Reported specificity in dogs for detection of thrombosis or DIC in the region of 25%.
• Reported specificity in cats for detection of DIC in the region of 50%.

Technique (intrinsic) limitations

• Does not provide a diagnosis with elevations occurring due to thrombosis, hemorrhage, DIC or many inflammatory/neoplastic conditions that are not overtly associated with hemostatic problems.

Technician (extrinsic) limitations

• Elevations may occur with hemolysis or activation of clotting ex-vivo.

Result Data

Further Reading

Publications

Refereed papers

• Recent references from VetMedResource and PubMed.
• Goggs R, Chan D L, Benigni L, Hirst C, Kellett-Gregory L, Fuentes V L (2014) Comparison of computed tomography pulmonary angiography and point-of-care tests for pulmonary thromboembolism diagnosis in dogs. J Small Anim Pract 55 (4), 190-197 PubMed.
• Nelson O L, Andreasen C (2003) The utility of plasma D-dimer to identify thromboembolic disease in dogs. J Vet Intern Med 17 (6), 830-834 PubMed.
• Dewhurst E, Cue S, Crawford E, Papasouliotis K (2008) A retrospective study of canine D-dimer concentrations measured using an immunometric "Point-of-Care" test. J Small Anim Pract 49 (7), 344-348 PubMed.
• Stokol T, Brooks M B, Erb H N & Mauldin G E (2000) D-dimer concentrations in healthy dogs and dogs with disseminated intravascular coagulation. Am J Vet Res 61, 393 PubMed.

Other sources of information

• Fundamentals of Veterinary Clinical Pathology (2008) Steven L Stockham & Michael A. Scott. 2nd edn. Blackwell Publishing.