Testing for antiphospholipid antibodies: Advances and best practices

Area of Science:

• Clinical Immunology
• Laboratory Medicine
• Rheumatology

Background:

• Antiphospholipid syndrome (APS) diagnosis depends on detecting antiphospholipid antibodies (aPL).
• Established criteria include lupus anticoagulant (LAC), anticardiolipin (aCL), and antibeta2-glycoprotein I (aβ2GPI) antibodies.
• Standardization efforts for LAC, aCL, and aβ2GPI assays have progressed, yet challenges remain.

Purpose of the Study:

• To review the technical aspects and clinical relevance of laboratory methods for antiphospholipid antibodies (aPL).
• To discuss the interpretation of aPL results in the diagnosis of antiphospholipid syndrome (APS).
• To evaluate the role of noncriteria aPL in risk stratification for APS patients.

Main Methods:

• Review of current guidelines and published literature on antiphospholipid antibody (aPL) testing.
• Analysis of technical challenges in lupus anticoagulant (LAC) measurement and solid-phase assays for aCL and aβ2GPI.
• Evaluation of the diagnostic and prognostic value of criteria and noncriteria aPL.

Main Results:

• Laboratory diagnosis of APS is complicated by methodological issues in LAC, aCL, and aβ2GPI assays.
• Antibody profiles and noncriteria aPL, such as anti-domain I (aDI) and anti-phosphatidylserine-prothrombin (aPS/PT), may aid in risk stratification.
• Noncriteria aPL lack added diagnostic value and are not recommended for routine APS diagnosis.

Conclusions:

• Despite standardization progress, technical challenges in aPL testing complicate APS diagnosis.
• While noncriteria aPL show potential for risk stratification, they are not currently part of diagnostic criteria.
• Further research into assay standardization and the clinical utility of specific antibody profiles is warranted for improved APS diagnosis and management.