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December 06, 2023
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Updated ACR/EULAR APS criteria require positive antiphospholipid antibody test

Fact checked byShenaz Bagha
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Key takeaways:

  • This is the first classification criteria revision for antiphospholipid syndrome since 2006.
  • The new guidelines have a specificity of 99% compared with 86% specificity of the previous guidelines.

Updated classification criteria for antiphospholipid syndrome require patients display at least one positive antiphospholipid antibody test within 3 years of a linked disease manifestation, according to new guidance from the ACR and EULAR.

“Since the introduction of the Sapporo criteria, advancements in our understanding of APS include better characterization of aPL-associated nonthrombotic clinical manifestations, identification of the role of traditional thrombosis risk factors in aPL-positive individuals, and risk stratification by aPL profile,” Medha Barbhaiya, MD, of the Hospital for Special Surgery, and colleagues wrote in the Annals of the Rheumatic Diseases.

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Updated classification criteria for APS require patients display at least one positive antiphospholipid antibody test within 3 years of a linked criterion, according to new guidance from the ACR and EULAR. Image: Adobe Stock

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Medha Barbhaiya

“Furthermore, the revised Sapporo criteria have been criticized for not incorporating evidence-based definitions, eg, aPL positivity, microvascular disease, or pregnancy morbidity, resulting in the inclusion of a heterogeneous group of “aPL-positive” patients with different risk profiles for research,” they added. “... Given the limitations of the current criteria, an international effort, jointly supported by the American College of Rheumatology (ACR) and EULAR, was initiated with the goal of using rigorous methodology to develop a new APS classification system based on a more modern disease understanding, allowing for the weighting of individual criterion, and demonstrating excellent operating characteristics with the highest possible specificity.”

To establish updated classification criteria for APS, specifically with an eye toward maximizing specificity, Barbhaiya and colleagues formed a 24-member ACR/EULAR steering committee that included physician experts from the United States, Europe and New Zealand, as well as three patient representatives. The process involved four phases. The first two phases hinged on establishing a wide set of criteria and then narrowing them down via modified Delphi and nominal group technique exercises. Meanwhile, committee members and expert collaborators received an emailed survey with open-ended questions regarding disease criteria.

During phase 3, the committee members determined which pieces of criteria belonged with clinical and laboratory domains. Finally, after narrowing the list of criteria further and assessing their weight, members validated each point via consensus provided by expert adjudicators.

According to the 2023 ACR/EULAR APS criteria, a patient must have at least one positive antiphospholipid antibody test performed within 3 years of the manifestation of a clinical disease criterion. Following that entry criterion, patients are to be evaluated based on weighted criteria across six clinical and two laboratory domains.

The clinical domains are macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic. The laboratory domains are lupus anticoagulant functional coagulation assays and solid-phase, enzyme-linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti–2-glycoprotein I antibodies.

If patients accrue scores of at least three points in the clinical and laboratory domains, they are determined to have APS, according to the updates criteria. Compared with the previous Sapporo guidelines from 2006, the new guidelines demonstrate a specificity of 99% vs. 86%, and a sensitivity of 84% vs. 99%.

“Using rigorous data-driven and expert-based methodology, including international multidisciplinary collaborators with APS expertise, methodologists and patients, we have incorporated heterogenous aPL-related clinical and laboratory manifestations into a set of hierarchically clustered, weighted and risk-stratified classification criteria reflecting current thinking about APS, providing high specificity and an improved foundation for APS research,” Barbhaiya and colleagues wrote.