ACR/EULAR (2023) APS classification criteria
| Entry criteria . |
|---|
| At least 1 documented clinical criterion,∗ listed hereafter (domains 1-6) |
| plus |
| A positive† aPL test (LA test or moderate-to-high titers of anticardiolipin or anti-β2-glycoprotein-I antibodies [IgG or IgM]) within three years of the clinical criterion |
| ↓ |
| If absent, do not attempt to classify as APS; if present, apply additive criteria |
| ↓ |
| Additive clinical and laboratory criteria |
| Do not count a clinical criterion if there is an equally, or more, likely explanation than APS. |
| Within each domain, only count the highest weighted criterion toward the total score. |
| Entry criteria . |
|---|
| At least 1 documented clinical criterion,∗ listed hereafter (domains 1-6) |
| plus |
| A positive† aPL test (LA test or moderate-to-high titers of anticardiolipin or anti-β2-glycoprotein-I antibodies [IgG or IgM]) within three years of the clinical criterion |
| ↓ |
| If absent, do not attempt to classify as APS; if present, apply additive criteria |
| ↓ |
| Additive clinical and laboratory criteria |
| Do not count a clinical criterion if there is an equally, or more, likely explanation than APS. |
| Within each domain, only count the highest weighted criterion toward the total score. |
| Clinical domains and criteria . | Weight . | Clinical domains and criteria . | Weight . |
|---|---|---|---|
| D1. Macrovascular (venous thromboembolism [VTE]) | D2. Macrovascular (arterial thrombosis [AT]) | ||
| VTE with high-risk profile | 1 | AT with high-risk CVD profile | 2 |
| VTE without high-risk profile | 3 | AT without high-risk CVD profile | 4 |
| D3. Microvascular | D4. Obstetric | ||
| Suspected, ≥1 of following: | 2 | ≥3 Consecutive (pre)embryonic loss(es) (at <10 w) and/or fetal death(s) (at 10 w, 0 d to 15 w, 6 d) | 1 |
| Livedo racemosa (exam) | |||
| Livedoid vasculopathy lesions (exam) | Fetal death (at 16 w, 0 d to 33 w, 6 d) in the absence of PreE or PI with severe features | 1 | |
| Acute/chronic aPL-nephropathy (exam or laboratory test) | |||
| Pulmonary hemorrhage (symptoms and imaging) | PreE with severe features (at <34 w, 0 d) or PI with severe features (at <34 w, 0 d) with/without fetal death | 3 | |
| Established, ≥1 of the following: | 5 | PreE with severe features (at <34 w, 0 d) and PI with severe features (<34 w, 0 d) with/without fetal death | 4 |
| Livedoid vasculopathy (pathology) | |||
| Acute/chronic aPL nephropathy (pathology) | |||
| Pulmonary hemorrhage (BAL or pathology) | |||
| Myocardial disease (imaging or pathology) | |||
| Adrenal hemorrhage (imaging or pathology) | |||
| D5. Cardiac valve | D6. Hematology | ||
| Thickening | 2 | Thrombocytopenia (lowest, 20-130 × 109/L) | 2 |
| Vegetation | 4 |
| Clinical domains and criteria . | Weight . | Clinical domains and criteria . | Weight . |
|---|---|---|---|
| D1. Macrovascular (venous thromboembolism [VTE]) | D2. Macrovascular (arterial thrombosis [AT]) | ||
| VTE with high-risk profile | 1 | AT with high-risk CVD profile | 2 |
| VTE without high-risk profile | 3 | AT without high-risk CVD profile | 4 |
| D3. Microvascular | D4. Obstetric | ||
| Suspected, ≥1 of following: | 2 | ≥3 Consecutive (pre)embryonic loss(es) (at <10 w) and/or fetal death(s) (at 10 w, 0 d to 15 w, 6 d) | 1 |
| Livedo racemosa (exam) | |||
| Livedoid vasculopathy lesions (exam) | Fetal death (at 16 w, 0 d to 33 w, 6 d) in the absence of PreE or PI with severe features | 1 | |
| Acute/chronic aPL-nephropathy (exam or laboratory test) | |||
| Pulmonary hemorrhage (symptoms and imaging) | PreE with severe features (at <34 w, 0 d) or PI with severe features (at <34 w, 0 d) with/without fetal death | 3 | |
| Established, ≥1 of the following: | 5 | PreE with severe features (at <34 w, 0 d) and PI with severe features (<34 w, 0 d) with/without fetal death | 4 |
| Livedoid vasculopathy (pathology) | |||
| Acute/chronic aPL nephropathy (pathology) | |||
| Pulmonary hemorrhage (BAL or pathology) | |||
| Myocardial disease (imaging or pathology) | |||
| Adrenal hemorrhage (imaging or pathology) | |||
| D5. Cardiac valve | D6. Hematology | ||
| Thickening | 2 | Thrombocytopenia (lowest, 20-130 × 109/L) | 2 |
| Vegetation | 4 |
| Laboratory domains and criteria . | Weight . | Laboratory domains and criteria . | Weight . |
|---|---|---|---|
| D7. aPL test by coagulation-based functional assay (LA test) | D8. aPL test by solid phase assay (aCL ELISA and/or aβ2GPI ELISA [persistent]) | ||
| Positive LA (single, 1 time) | 1 | Moderate-to-high-positive (IgM) (aCL and/or aβ2GPI) | 1 |
| Positive LA (persistent) | 5 | Moderate-to-high-positive (IgG) (aCL and/or aβ2GPI) | 4 |
| High-positive (IgG) (aCL or aβ2GPI) | 5 | ||
| High-positive (IgG) (aCL and aβ2GPI) | 7 | ||
| Total score | |||
| Classify as APS for research purposes if there are at least 3 points from clinical domains AND at least 3 points from laboratory domains | |||
| Laboratory domains and criteria . | Weight . | Laboratory domains and criteria . | Weight . |
|---|---|---|---|
| D7. aPL test by coagulation-based functional assay (LA test) | D8. aPL test by solid phase assay (aCL ELISA and/or aβ2GPI ELISA [persistent]) | ||
| Positive LA (single, 1 time) | 1 | Moderate-to-high-positive (IgM) (aCL and/or aβ2GPI) | 1 |
| Positive LA (persistent) | 5 | Moderate-to-high-positive (IgG) (aCL and/or aβ2GPI) | 4 |
| High-positive (IgG) (aCL or aβ2GPI) | 5 | ||
| High-positive (IgG) (aCL and aβ2GPI) | 7 | ||
| Total score | |||
| Classify as APS for research purposes if there are at least 3 points from clinical domains AND at least 3 points from laboratory domains | |||
ACR/EULAR (2023) APS classification criteria modified from Barbhaiya et al.1
aCL and aβ2GPI moderate (40-79 U) and high (≥80 U) thresholds should be determined based on standardized ELISA results, not based on other testing modalities such as new automated platforms with variations of the solid phase (eg, magnetic microparticles and microspheres) and various detection systems (eg, chemiluminescent immunoassay, multiplex flow immunoassay, or flow cytometry).
AT, arterial thrombosis; BAL, bronchoalveolar lavage; CVD, cardiovascular disease; D, domain; d, day; VTE, venous thrombosis or embolism; w, week(s).
For detailed definitions of the clinical criteria and documentation, readers are referred to the 2023 ACR/EULAR APS classification criteria document.1
LA assay performed and interpreted based on the International Society of Thrombosis and Hemostasis guidelines.46