Assay

Cardiolipin Antibodies (Anti-Phospholipid Antibodies)

Key Words

Cardiolipin Antibodies Anti-Phospholipid Antibodies ACl ACA

Specimen Collection

Serum (brown)

Turnaround time

7 days

Test indications

These are a family of antibodies (Cardiolipin, b2-glycoprotein-1 and the Lupus Anti-Coagulant) useful in the investigation of the anti-phospholipid syndrome. This may be primary or secondary to SLE. Patients with the ‘anti-phospholipid syndrome’ may be positive for both the lupus anti-coagulant and for the cardiolipin autoantibodies or for only one of these assays. Therefore samples should be sent for both tests. (Please note that the lupus anticoagulant assay is performed in the Haematology Laboratory.)

The diagnosis of the anti phospholipid syndrome requires the appropriate clinical setting (see below) together with persistently (longer than 6- 8 weeks) elevated anti phospholipid antibodies. The syndromes associated with anti-phospholipid antibodies are treatable and it is appropriate to seek its presence in the following groups of patients:

• Women with recurrent unexplained foetal loss
• Young patients with stroke, myocardial infarction or transient ischaemic attacks - without other predisposing factors
• Young patients with recurrent venous or arterial thromboses
• Patients with unexplained thrombocytopenia
• Patients with chronic false positive VDRL
• Patients with SLE as part of assessment of thrombotic risk in pregnancy 

It has been noted that the level of anti-cardiolipin antibodies may fall during a thrombotic event or miscarriage. Thus a normal result obtained at this time does not rule out the anti-phospholipid syndrome and repeat testing during convalescence (at least 6-8 weeks later, ideally 12 weeks) is needed.

Methodology

Enzyme immunoassay

Interferences

No known methodological interferences

Reference Range

Negative        <10 GPL-U/mL

Weak Positive 10-40 GPL-U/mL

Positive          >40 GPL-U/mL

Analytical error

Contact the Laboratory (x8454)

Reference change value

N/A