Performance of serologic tests used to detect heartworm infection in cats

J Am Vet Med Assoc. 2000 Mar 1;216(5):693-700. doi: 10.2460/javma.2000.216.693.

Abstract

Objective: To compare heartworm serum antibody (Ab) and antigen (Ag) test results, using commercial laboratories and in-house heartworm test kits, with necropsy findings in a population of shelter cats.

Design: Prospective study.

Animals: 330 cats at an animal shelter.

Procedure: Between March and June 1998, 30 ml of blood was collected from the cranial and caudal venae cavae of 330 cats that were euthanatized at a local animal shelter. Results of heartworm Ab and Ag serologic tests for heartworm infection were compared with necropsy findings in this population of cats, using commercial laboratories and in-house test kits to measure serum Ab and Ag concentrations.

Results: On necropsy, adult Dirofilaria immitis were found in 19 of 330 (5.8%) cats. Combining results from serum Ab and Ag tests achieved higher sensitivities than using serum Ab and Ag test results alone (i.e., maximum sensitivities of 100% vs 89.5%, respectively, whereas use of serum Ag and Ab test results alone achieved higher specificities compared with the use of a combination of serum Ab and Ag results (i.e., maximum specificities of 99.4% vs 92.9%, respectively).

Conclusions and clinical relevance: On the basis of our findings, if a cat has clinical signs that suggest heartworm disease despite a negative heartworm serum Ab test result, an alternative heartworm Ab test, a heartworm Ag test, thoracic radiography, or two-dimensional echocardiography should be performed.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Antibodies, Helminth / blood*
  • Antigens, Helminth / blood*
  • Cat Diseases / diagnosis*
  • Cats
  • Dirofilaria immitis / immunology*
  • Dirofilariasis / diagnosis*
  • Enzyme-Linked Immunosorbent Assay / veterinary
  • False Negative Reactions
  • False Positive Reactions
  • Female
  • Hemolysis
  • Lipids / blood
  • Male
  • Prospective Studies
  • Reagent Kits, Diagnostic / veterinary
  • Sensitivity and Specificity

Substances

  • Antibodies, Helminth
  • Antigens, Helminth
  • Lipids
  • Reagent Kits, Diagnostic