Table 4.

Comparison of isotypes of anti-ß₂ glycoprotein I (anti-ß₂-GPI) with serologic tests in systemic lupus erythematosus.

Factor	IgG Anti-ß₂-GPI Present^*, %	IgG Anti-ß₂-GPI Absent, %	p	OR (95% CI)
Coombs positivity	36.8	14.5	0.0010	3.37 (1.68–6.75)
Lupus anticoagulant (by RVVT)	86.1	26.2	< 0.0001	17.4 (7.22–41.8)
Anticardiolipin	97.6	59.2	< 0.0001	28.2 (3.85–206)
Anti-dsDNA	74.4	56.4	0.0254	2.25 (1.12–4.53)
Anti-Sm	14.3	18.5	0.6809	0.73 (0.30–1.77)
False-positive test for syphilis	51.3	13.2	< 0.0001	6.92 (3.55–13.5)
Low CH50	28.2	12.5	0.0122	2.75 (1.32–5.73)
Low C3	69.8	51.2	0.0187	2.20 (1.13–4.28)
Low C4	67.4	45.6	0.0069	2.48 (1.29–4.76)
Anti-Ro/SSa	21.4	30.0	0.2973	0.64 (0.30–1.35)
ESR	88.4	77.0	0.0913	2.27 (0.88–5.86)
	IgM Anti-ß₂-GPI Present	IgM Anti-ß₂-GPI Absent
Coombs positivity	25.0	14.2	0.0070	2.01 (1.24–3.28)
Lupus anticoagulant (by RVVT)	52.4	25.2	< 0.0001	3.28 (2.21–4.86)
Anticardiolipin	84.0	57.0	< 0.0001	3.96 (2.40–6.55)
Anti-dsDNA	63.2	56.3	0.1677	1.33 (0.90–1.98)
Anti-Sm	13.1	19.3	0.1254	0.63 (0.36–1.11)
False positive test for syphilis	35.1	11.5	< 0.0001	4.15 (2.62–6.57)
Low CH50	17.7	12.5	0.1405	1.50 (0.88–2.55)
Low C3	58.4	51.1	0.1434	1.35 (0.91–1.96)
Low C4	52.8	45.6	0.1438	1.33 (0.91–1.96)
Anti-Ro/SSA	21.8	31.0	0.0414	0.62 (0.39–0.98)
ESR	78.4	77.5	0.9069	1.06 (0.66–1.68)
	IgA Anti-ß₂-GPI Present	IgA Anti-ß₂-GPI Absent
Coombs positivity	20.7	14.7	0.0932	1.51 (0.94–2.42)
Lupus anticoagulant (by RVVT)	48.7	24.6	< 0.0001	2.91 (2.03–4.18)
Anticardiolipin	77.5	57.1	< 0.0001	2.58 (1.73–3.87)
Anti-dsDNA	76.9	52.4	< 0.0001	3.02 (2.03–4.50)
Anti-Sm	24.2	16.8	0.0373	1.58 (1.04–2.41)
False positive test for syphilis	28.6	11.8	< 0.0001	2.98 (1.92–4.62)
Low CH50	22.5	10.9	0.0004	2.37 (1.49–3.77)
Low C3	70.6	47.5	< 0.0001	2.66 (1.83–3.86)
Low C4	62.5	42.7	< 0.0001	2.23 (1.56–3.19)
Anti-Ro/SSA	32.9	28.7	0.3289	1.22 (0.84–1.77)
ESR	88.7	74.8	0.0001	2.64 (1.56–4.45)

↵* Positive value ≥ 20 phospholipid units. RVVT: Russell viper venom time; ESR: erythrocyte sedimentation rate.