2118. β-2-glycoprotein I, IgA antibodies

β-2-glycoprotein I is a glycosylated plasma protein with anticoagulant properties.

Testing for antibodies to β-2-glycoprotein I is used to diagnose antiphospholipid syndrome in cases of pregnancy complications, before starting oral contraceptives, in oncology, in patients with low platelet counts, and after a stroke or myocardial infarction. APS manifests as venous thrombosis, pulmonary hypertension, migraine, seizures, and psychiatric disorders.

Elevated IgA antibody levels indicate an acute course of the disease. A complete blood count, biochemical blood test, coagulogram, and anticardiolipin antibodies are tested as part of a comprehensive assessment.

Antiphospholipid syndrome (APS) is an autoimmune inflammatory disease characterized by recurrent venous or arterial thrombosis and recurrent pregnancy loss. Its development is associated with the presence of antibodies to phospholipid determinants, which disrupt the normal function of the vascular system. The laboratory criteria for the diagnosis of APS (XII International Symposium on the Diagnosis of APS, Sapporo, 2006) include IgA, IgM, and IgG antibodies to β-2-glycoprotein I.

This test has high diagnostic sensitivity and high specificity for the diagnosis of APS compared with anticardiolipin antibodies and lupus anticoagulant.

Exclusion of APS as one of the forms of thrombophilia (especially at a young age) in cases of:

• venous/arterial thrombosis (deep vein thrombosis, myocardial infarction, stroke, pulmonary embolism, infarction of internal organs, livedo reticularis, leg ulcers, transient cerebrovascular events, etc.);
• recurrent pregnancy loss, fetal loss syndrome at various stages of pregnancy, infertility, bleeding during pregnancy, development of preeclampsia and eclampsia, placental insufficiency with fetal growth restriction, premature placental abruption, stillbirths in the medical history;
• before starting oral contraceptives, before prescribing hormone replacement therapy, and for monitoring during treatment with these medications.

The test is indicated in patients with cardiovascular disease to assess the risk or cause of thrombotic complications (stroke, myocardial infarction), autoimmune diseases, any type of cancer, prolonged activated partial thromboplastin time (aPTT) detected on a coagulogram, negative results for other laboratory markers of APS, HELLP syndrome, a positive Wassermann reaction (RW), thrombocytopenia, and hemolytic anemia.

Repeat testing is performed after a positive initial result to establish the diagnosis (after 12 weeks).

• Venous blood

In order to exclude factors that may affect the test results, we recommend to follow the preparation rules: