The 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria
Authors: Barbhaiya Medha , Zuily Stephane , Naden Ray , Hendry Alison , Manneville Florian , Amigo Mary‐Carmen , Amoura Zahir , Andrade Danieli , Andreoli Laura , Artim‐Esen Bahar , Atsumi Tatsuya , Avcin Tadej , Belmont H. Michael , Bertolaccini Maria Laura , Branch D. Ware , Carvalheiras Graziela , Casini Alessandro , Cervera Ricard , Cohen Hannah , Costedoat‐Chalumeau Nathalie , Crowther Mark , de Jesus Guilherme , Delluc Aurelien , Desai Sheetal , De Sancho Maria , Devreese Katrien M. , Diz‐Kucukkaya Reyhan , Duarte‐Garcia Ali , Frances Camille , Garcia David , Gris Jean‐Christophe , Jordan Natasha , Leaf Rebecca K. , Kello Nina , Knight Jason S. , Laskin Carl , Lee Alfred I. , Legault Kimberly , Levine Steve R. , Levy Roger A. , Limper Maarten , Lockshin Michael D. , Mayer‐Pickel Karoline , Musial Jack , Meroni Pier Luigi , Orsolini Giovanni , Ortel Thomas L. , Pengo Vittorio , Petri Michelle , Pons‐Estel Guillermo , Gomez‐Puerta Jose A. , Raimboug Quentin , Roubey Robert , Sanna Giovanni , Seshan Surya V. , Sciascia Savino , Tektonidou Maria G. , Tincani Angela , Wahl Denis , Willis Rohan , Yelnik Cecile , Zuily Catherine , Guillemin Francis , Costenbader Karen , Erkan Doruk ,   the ACR/EULAR APS Classification Criteria Collaborators
Published: August 2023

Objective

To develop new antiphospholipid syndrome (APS) classification criteria with high specificity for use in observational studies and trials, jointly supported by the American College of Rheumatology (ACR) and EULAR.

Methods

This international multidisciplinary initiative included 4 phases: 1) Phase I, criteria generation by surveys and literature review; 2) Phase II, criteria reduction by modified Delphi and nominal group technique exercises; 3) Phase III, criteria definition, further reduction with the guidance of real‐world patient scenarios, and weighting via consensus‐based multicriteria decision analysis, and threshold identification; and 4) Phase IV, validation using independent adjudicators’ consensus as the gold standard.

Results

The 2023 ACR/EULAR APS classification criteria include an entry criterion of at least one positive antiphospholipid antibody (aPL) test within 3 years of identification of an aPL‐associated clinical criterion, followed by additive weighted criteria (score range 1–7 points each) clustered into 6 clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and 2 laboratory domains (lupus anticoagulant functional coagulation assays, and solid‐phase enzyme‐linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti–β2‐glycoprotein I antibodies). Patients accumulating at least 3 points each from the clinical and laboratory domains are classified as having APS. In the validation cohort, the new APS criteria versus the 2006 revised Sapporo classification criteria had a specificity of 99% versus 86%, and a sensitivity of 84% versus 99%.

Conclusion

These new ACR/EULAR APS classification criteria were developed using rigorous methodology with multidisciplinary international input. Hierarchically clustered, weighted, and risk‐stratified criteria reflect the current thinking about APS, providing high specificity and a strong foundation for future APS research.