Cardiolipin Antibodies

This test measures serum concentrations of immunoglobulin G and immunoglobulin M antibodies in relation to the phospholipid cardiolipin. These antibodies appear in some lupus erythematosus (LE) patients whose serum also contains a coagulation inhibitor (lupus anticoagulant). They also appear in some patients who don't fulfill all the diagnostic criteria for LE but who experience recurrent episodes of spontaneous thrombosis, fetal loss, or thrombocytopenia. Serum concentrations of cardiolipin antibodies are measured by enzyme-linked immunosorbent assay.

Purpose

To aid diagnosis of cardiolipin antibody syndrome in patients with or without LE who experience recurrent episodes of spontaneous thrombosis, fetal loss, or thrombocytopenia.

Patient preparation

• Tell the patient that this test helps diagnose cardiolipin antibody syndrome and lupus erythematosus.
• Tell him that he needn't restrict food or fluids before the test.
• Tell him that the test requires a blood sample and who will perform the venipuncture and when.
• Reassure him that although he may experience transient discomfort from the needle puncture and the tourniquet, collecting the sample takes less than 3 minutes.

Procedure and posttest care

• Perform a venipuncture, and collect the sample in a 5-ml red-top tube.
• If a hematoma develops at the venipuncture site, apply warm soaks.

Precautions

Handle the sample gently to prevent hemolysis, and send it to the laboratory immediately.

Reference values

Cardiolipin antibody results are reported as negative or positive. A positive result is titered.

Abnormal findings

A positive result along with a history of recurrent spontaneous thrombosis, fetal loss, or thrombocytopenia suggests cardiolipin antibody syndrome. Treatment may involve anticoagulant or platelet inhibitor therapy.

Interfering factors

• Hemolysis due to rough handling of the sample.
• Failure to send the sample to the laboratory immediately.