Table 1.

Severity classification of antiphospholipid antibodies.

Grade	Definition
0	Not applicable to APS
I	No treatment required, no organ damage, and no decline in ADL. 1) No antiplatelet or anticoagulation therapy and no new onset of thrombosis within the past year. 2) A history of pregnancy complications only, without a history of thrombosis. 3) There is a history of thrombosis but no evidence of organ damage and no interference with daily life.
II	The patient is treated but stable, with no organ damage and no ADL decline.
	The patient is on antiplatelet or anticoagulation therapy and has no new onset of thrombosis within the past year; there is a history of thrombosis but no organ damage and no interference with daily life.
III	Recurrent thrombosis despite treatment, mild organ damage, and decreased ADL. 1) Recurrent thrombosis: New thrombosis within the past year despite antiplatelet or anticoagulation therapy. 2) Mild organ damage: permanent organ damage due to APS (cerebral infarction, myocardial infarction, pulmonary infarction, renal damage, vision loss, or visual field abnormality, among others) but little or no decline in ADL.
IV	During treatment for antiphospholipid antibody-related diseases, during pregnancy management, with moderate organ damage or decline in ADL. 1) Antiphospholipid antibody-related disease: In addition to APS with a confirmed diagnosis, ongoing immunosuppressive therapy for antiphospholipid antibody-related thrombocytopenia, neuropathy. 2) Pregnancy management: she had antiplatelet therapy or anticoagulation therapy within the past year to prevent thrombosis during pregnancy or pregnancy complications. 3) Moderate organ damage: there is permanent vital organ damage (cerebral infarction, myocardial infarction, pulmonary infarction, renal impairment, vision loss, or visual field abnormality, among others) due to APS and ADL being decreased.
V	Catastrophic APS, new or relapse of antiphospholipid antibody-related disease requiring treatment, pregnancy complications during therapy, severe organ damage, and decreased ADL. 1) CAPS: onset within the past year, requiring multidisciplinary treatment. 2) Antiphospholipid antibody-related disease: In addition to APS with a confirmed diagnosis, immunosuppressive therapy for antiphospholipid antibody-related thrombocytopenia, neuropathy has been initiated within the past year, or treatment has been intensified due to relapse. 3) Severe organ damage: significant loss of ADL such as the need for assistance due to permanent vital organ damage caused by APS (cerebral infarction, myocardial infarction, pulmonary infarction, renal impairment, vision loss, or visual field abnormality).

ADL = activity of daily life, APS = antiphospholipid antibody syndrome, CAPS = catastrophic antiphospholipid syndrome.