. Author manuscript; available in PMC: 2016 May 24.

Published in final edited form as: Hematology Am Soc Hematol Educ Program. 2015;2015:53–60. doi: 10.1182/asheducation-2015.1.53

Table 1.

Summary of the Sydney Consensus Statement on Classification of APS

Antiphospholipid antibody syndrome (APS) is present if at least one of the clinical criteria and one of the laboratory criteria are met
Clinical criteria Vascular thrombosis One or more documented episodes of arterial, venous, or small vessel thrombosis in any tissue. Thrombosis must be confirmed by objective validated criteria. For histologic confirmation, thrombosis should be present without significant vessel wall inflammation. Pregnancy morbidity One or more unexplained deaths of a morphologically normal fetus at or beyond the 10th week of gestation, with normal fetal morphology documented by ultrasound or direct examination of the fetus, or One or more premature births of a morphologically normal neonate before the 34th week of gestation because of eclampsia or preeclampsia diagnosed by standard definitions, or recognized features of placental insufficiency, or Three or more unexplained consecutive spontaneous abortions before the 10th week of gestation, with maternal or hormonal abnormalities, and maternal and paternal chromosomal causes excluded. Investigators are strongly advised to classify subjects with obstetrical morbidity according to groups a, b, and c in populations of patients with more than one type of pregnancy morbidity.
Laboratory criteria Lupus anticoagulant (LA) present in plasma, on 2 or more occasions at least 12 weeks apart, detected according to the guidelines of the International Society of Thrombosis and Hemostasis. Anticardiolipin antibody (aCL) of IgG and/or IgM isotype in serum or plasma, present in medium or high titer (>40 GPL or MPL, or >99th percentile), on 2 or more occasions, at least 12 weeks apart, measured by a standardized ELISA. Anti- β₂ glycoprotein-I antibody (anti- β₂GPI) of IgG and/or IgM isotype in serum or plasma with a titer >99th percentile, on 2 or more occasions, at least 12 weeks apart, measured by a standardized ELISA. Investigators are strongly urged to classify APS patients into one of the following categories: I >1 laboratory criteria present (any combination) IIa LA present alone IIb aCL present alone IIc anti- β₂GPI present alone

Antiphospholipid antibody syndrome (APS) is present if at least one of the clinical criteria and one of the laboratory criteria are met

Clinical criteria

Vascular thrombosis

One or more documented episodes of arterial, venous, or small vessel thrombosis in any tissue. Thrombosis must be confirmed by objective validated criteria. For histologic confirmation, thrombosis should be present without significant vessel wall inflammation.
Pregnancy morbidity
1. One or more unexplained deaths of a morphologically normal fetus at or beyond the 10th week of gestation, with normal fetal morphology documented by ultrasound or direct examination of the fetus, or
2. One or more premature births of a morphologically normal neonate before the 34th week of gestation because of eclampsia or preeclampsia diagnosed by standard definitions, or recognized features of placental insufficiency, or
3. Three or more unexplained consecutive spontaneous abortions before the 10th week of gestation, with maternal or hormonal abnormalities, and maternal and paternal chromosomal causes excluded.

Investigators are strongly advised to classify subjects with obstetrical morbidity according to groups a, b, and c in populations of patients with more than one type of pregnancy morbidity.

Laboratory criteria

Lupus anticoagulant (LA) present in plasma, on 2 or more occasions at least 12 weeks apart, detected according to the guidelines of the International Society of Thrombosis and Hemostasis.
Anticardiolipin antibody (aCL) of IgG and/or IgM isotype in serum or plasma, present in medium or high titer (>40 GPL or MPL, or >99th percentile), on 2 or more occasions, at least 12 weeks apart, measured by a standardized ELISA.
Anti- β₂ glycoprotein-I antibody (anti- β₂GPI) of IgG and/or IgM isotype in serum or plasma with a titer >99th percentile, on 2 or more occasions, at least 12 weeks apart, measured by a standardized ELISA.

Investigators are strongly urged to classify APS patients into one of the following categories:

I
>1 laboratory criteria present (any combination)
IIa
LA present alone
IIb
aCL present alone
IIc
anti- β₂GPI present alone