From the Guidelines
Elevated levels of anticardiolipin antibody IgG are associated with antiphospholipid syndrome (APS), and the presence of these antibodies can increase the risk of blood clots, pregnancy complications, and other health issues, as supported by the most recent study 1. The test for anticardiolipin antibody IgG measures the level of IgG antibodies against cardiolipin, a phospholipid found in cell membranes.
- Normal values are generally less than 20 GPL units (IgG phospholipid units), with levels above 40 GPL units considered strongly positive, as defined in the 2024 guideline for the primary prevention of stroke 1.
- The test is typically ordered when a patient presents with unexplained blood clots, recurrent miscarriages, or certain neurological symptoms.
- If elevated levels are detected, the test should be repeated after 12 weeks to confirm the diagnosis, as transient elevations can occur during infections or with certain medications. Some key points to consider:
- The 2023 ACR/EULAR classification criteria attribute a lower weight to a single aCL or aβ2GPI, even if it is a high titer, as mentioned in the study 1.
- Triple aPL positivity (LA, aCL, and aβ2GPI positive) is associated with a high risk of a first thrombotic event and recurrence, as supported by the study 1.
- Treatment for patients with positive anticardiolipin antibodies and clinical manifestations often includes anticoagulation therapy such as low-dose aspirin, heparin, or warfarin, depending on the clinical situation and risk factors, as recommended in the 2024 guideline for the primary prevention of stroke 1. The presence of anticardiolipin antibody IgG is thought to promote clotting by interfering with phospholipid-dependent coagulation processes and platelet function, disrupting the normal balance between clotting and bleeding, and therefore, anticoagulation therapy is often necessary to prevent thrombotic events, as supported by the study 1.
From the Research
Anticardiolipin Ab IgG
- Anticardiolipin antibodies, including IgG, are a type of antiphospholipid antibody (aPL) associated with antiphospholipid syndrome (APS) 2, 3, 4.
- APS is an autoimmune disorder characterized by thrombosis and/or pregnancy morbidity in the presence of aPL 3.
- The presence of anticardiolipin antibodies, particularly IgG, is a key criterion for the diagnosis of APS 2, 4.
- Patients with triple positivity (i.e., positivity for lupus anticoagulant, anti-cardiolipin, and anti-β2-glycoprotein I antibodies) are at high risk of thrombotic events, and the detection of triple positivity is dependent on the solid phase assay used 5.
- The treatment for APS is based on the patient's clinical status, presence of an underlying autoimmune disease, and history of thrombotic events, and may include anticoagulation therapy with warfarin or direct oral anticoagulants 2, 3, 4.
- The choice of anticoagulant therapy may depend on the patient's specific clinical characteristics, such as the presence of triple positivity or a history of thrombotic events 4, 6.