Test Indications:
Phospholipid Antibodies occur in patients with a variety of manifestations:
* Thrombotic events both arterial and venous
* Obstetric abnormalities: unexplained fetal death, premature birth, placental insufficiency,  and severe preeclampsia
* Cutaneous abnormalities: livido reticularis, pyoderma gangrenosum
* Peripheral blood cytopenia, thrombocytopenia, or hemolytic anemia
 
Diagnosis of antiphospholipid syndrome requires a positive test result of either cardiolipin,    β2-Glycoprotein or lupus anticoagulant on more than one occasion separated by at least 12 weeks, in addition to either thrombosis, fetal loss, or thrombocytopenia. Only IgG and IgM antibodies are tested as IgA antibodies lack specificity.

These antibodies are also known to be more frequent in patients with systemic rheumatic diseases and are also produced in response to infections and as a non-autoimmune epiphenomenon of thrombotic events.

Anti-β2-Glycoprotein 1 IgG         0.0 – 20.0             AU/ml

Anti-β2-Glycoprotein 1 IgM         0.0 – 9.9               AU/ml

Anti-Cardiolipin IgG                     0.0 – 20.0             GPL U/ml

Anti-Cardiolipin IgM                     0.0 – 9.9               MPL U/ml

A negative result does not necessarily exclude autoimmune disease.  Positive results should not be interpreted in isolation and must be correlated with relevant clinical findings.

For single-positive IgM:

Isolated IgM positivity is frequently transient and non-specific. Clinical significance is low unless persistent and accompanied by other aPL.

For single-positive IgG:

Single IgG positivity should be confirmed after ≥12 weeks. Clinical interpretation should consider titer level and associated markers.

For double-positive patterns:

Double aPL positivity increases the likelihood of APS and is less likely to represent analytical or transient noise.

For triple-positive patterns:

Triple positivity represents a high-risk APS profile with strong clinical significance. Persistence and clinical evaluation are recommended.

Method of Analysis:
The IDS assays are in vitro diagnostic devices intended for the quantitative determination of specific IgG or IgM antibodies directed against β2-Glycoprotein I or Cardiolipin in human serum on the IDS system.  Each assay is based on chemiluminescence technology. Patient serum is incubated with magnetic particles coated with the specific antigen. Following the washing step after the first incubation, anti-human IgG or IgM antibody labelled with acridinium, followed by a subsequent incubation step. The magnetic particles are captured using a magnet and a wash step performed to remove any unbound analyte. Trigger reagents are added; the resulting light emitted by the acridinium label is directly proportional to the concentration of analyte in the original sample. 

References: 

IDS β2-Glycoprotein I IgG Instructions for Use IS-AI1502 V08 17-11-2025 

IDS β2-Glycoprotein I IgM Instructions for Use IS-AI1602 V09 18-11-2025

IDS Cardiolipin IgG Instructions for Use IS-AI1501 V12 17-11-2025

IDS Cardiolipin IgM Instructions for Use IS-AI1601 V08 17-11-2025

Anti-β2-Glycoprotein 1 IgG         0.0 – 867.0          AU/ml

Anti-β2-Glycoprotein 1 IgM         0.0 – 300.0          AU/ml

Anti-Cardiolipin IgG                     0.0 – 640.0          GPL U/ml

Anti-Cardiolipin IgM                     0.0 – 300.0          MPL U/ml