Coagulation laboratory tests
Anticardiolipin antibodies

Topic Completed: 1 June 2012

Revised: 7 January 2019, last major update June 2012

Copyright: (c) 2002-2016,, Inc.

PubMed Search: Anticardiolipin antibodies [title]

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Cite this page: Parsons J. Anticardiolipin antibodies. website. Accessed August 6th, 2020.
Definition / general
  • One of the two main types of antiphospholipid antibodies (other is lupus anticoagulant) often seen in conjunction with beta2 - glycoprotein antibodies

  • Indications:
    • Patients with venous thromboembolism (particularly if no family history or associated with autoimmune disease)
    • Unexplained stroke (young person or autoimmune disease), cerebral venous thrombosis, recurrent or late pregnancy loss
    • Test may be considered for arterial thrombosis, particularly in young patient or no documented atherosclerosis

  • Specimen:
    • Serum (red top)

  • Methodology:
    • ELISA test to recognize proteins (not actually cardiolipin) bound to a microtiter plate
    • Tests for anti - prothrombin and anti - beta2 - GPI antibodies have had limited prospective studies
    • IgG recommended to evaluated hypercoagulability (risk with IgM or IgA antibodies is uncertain)
    • Increased titers are most closely associated with hypercoagulability
    • 200 - 400x more sensitive than VDRL, but patient with syphilitic infection may have positive anticardiolipin antibody test results
    • High sensitivity plates have greater antigenic density on microtiter plate, may be irradiated for greater antigenic density and to facilitate bivalent bonding of plasma antibodies
    • 62% positivity in patients with SLE or other autoimmune results
    • To demonstrate antibody persistence, positive test must be confirmed by repeat testing after 6 weeks
    • Transient antibodies are not strongly associated with thrombosis
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