Canis ISSN: 2398-2942

Anti-platelet antibody

Synonym(s): APlA

Contributor(s): Vetstream Ltd


  • Platelet factor 3 (PF3) test detects platelet damage caused by antibody, therefore indirect test for antibody.
  • More direct tests: anti-megakaryocyte antibody and more recent anti-platelet antibody test.


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Platelet-associated antibody tests

  • Immunofluorescence, ELISA, radioimmunoassay, electron microscopy using a staphylococcal protein A-colloidal gold conjugate, flow cytometry.
  • Direct methods: use whole blood, EDTA sample.
  • Indirect methods: sample serum or plasma tested against pooled normal platelets.

Anti-megakaryocyte antibody test

  • Detects megakaryocyte-associated immunoglobulin.
  • Positive test may also suggest presence of antibodies against platelets.
  • May be more sensitive than PF3 test.

Platelet factor 3 test

  • Platelets damaged by antibody release increased PF3.
  • Determined by accelerated activated partial thromboplastin time (APTT).
  • Indirect.
  • Rarely used due to many false negatives.


  • Limited in UK.
  • Cambridge University Vet School (UK) performs antibody test (EDTA sample).



  • Direct anti-platelet antibody tests: low sensitivity due to low numbers of platelets.
  • Indirect tests: 70-95% sensitive.


  • Indirect tests: false positives in patients with other immune-mediated diseases, non-immune-mediated thrombocytopenia, neoplasia.

Technique (intrinsic) limitations

  • Absolute confirmation of immune-mediated disease.
  • Information about source of anti-platelet antibody.

Technician (extrinsic) limitations

  • Depends on method used.

Result Data

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Further Reading


Refereed papers

  • Recent references from VetMedResource and PubMed.
  • Campbell K L et al (1984) Application of the enzyme-linked immunosorbent assay for the detection of anti-platelet antibodies in dogs. Am J Vet Res 45, 2561.
  • McVey D S & Shuman W S (1989) Detection of antiplatelet immunoglobulin in thrombocytopenic dogs. Vet Immuno Immunopathol 22, 101.