Felis ISSN 2398-2950

Hematology: D-dimers

Contributor(s): Yvonne McGrotty, Mayank Seth

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

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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 in dogs.
  • The sensitivity of D-dimer elevations for detecting DIC Disseminated intravascular coagulation 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

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Tholen I, Weingart C, Kohn B (2009) Concentration of D-dimers in healthy cats and sick cats with and without disseminated intravascular coagulation (DIC). J Feline Med Surg 10, 842-846.
  • Brazzell J L, Borjesson D L (2007)Evaluation of plasma antithrombin activity and D-dimer concentration in populations of healthy cats, clinically ill cats, and cats with cardiomyopathy. Vet Clin Pathol 36(1), 79-84 PubMed.

Other sources of information

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


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