Reference intervals for aCL and anti-β2GPI IgAGM antibodies in a large health-inspection population: a foundational study for combined-isotype assay interpretation.
Combined-isotype anticardiolipin (aCL) and anti-β2-glycoprotein I (anti-β2GPI) immunoglobulin A, G and M (IgAGM) assays are used in current laboratory practice, but their disease relevance and clinical interpretation remain incompletely defined. This study aimed to establish 99th-percentile reference intervals for aCL IgAGM and anti-β2GPI IgAGM in a large general healthy population and to provide a basis for future disease-oriented evaluation.
A total of 7846 eligible individuals who underwent health inspection were included in the analysis. Plasma aCL IgAGM and anti-β2GPI IgAGM were measured by ELISA. A physiologically normal reference subgroup was defined by excluding predefined laboratory abnormalities at the retained index visit (n=989). Retrospective contextual analyses were also performed in systemic lupus erythematosus (SLE) and coronary heart disease (CHD) populations with historical IgAGM results.
Among 7846 individuals (5170 male and 2676 female; age 15-90 years), the 99th percentiles were 35.4 relative units (RU)/mL for aCL and 51.7 RU/mL for anti-β2GPI. In the physiologically normal reference subgroup, the corresponding values were 23.33 RU/mL and 46.25 RU/mL. Sex differences were significant for both antibodies in the overall population and in the physiologically normal subgroup, and aCL showed age-related increases at the upper tail. In retrospective analyses, SLE showed higher proportions above all four cut-offs than CHD, with significance for anti-β2GPI at both the general health participant cut-off (11.4% vs 4.5%, p=0.0425) and the physiologically normal cut-off (12.3% vs 4.5%, p=0.0200). Exploratory analyses linked antibody levels to triglyceride-related profiles.
Assay-specific 99th-percentile reference intervals for aCL IgAGM and anti-β2GPI IgAGM were established in a large health-inspection population and a physiologically normal reference subgroup. These findings provide a practical interpretive framework for combined-isotype assays and support future disease-oriented evaluation.
A total of 7846 eligible individuals who underwent health inspection were included in the analysis. Plasma aCL IgAGM and anti-β2GPI IgAGM were measured by ELISA. A physiologically normal reference subgroup was defined by excluding predefined laboratory abnormalities at the retained index visit (n=989). Retrospective contextual analyses were also performed in systemic lupus erythematosus (SLE) and coronary heart disease (CHD) populations with historical IgAGM results.
Among 7846 individuals (5170 male and 2676 female; age 15-90 years), the 99th percentiles were 35.4 relative units (RU)/mL for aCL and 51.7 RU/mL for anti-β2GPI. In the physiologically normal reference subgroup, the corresponding values were 23.33 RU/mL and 46.25 RU/mL. Sex differences were significant for both antibodies in the overall population and in the physiologically normal subgroup, and aCL showed age-related increases at the upper tail. In retrospective analyses, SLE showed higher proportions above all four cut-offs than CHD, with significance for anti-β2GPI at both the general health participant cut-off (11.4% vs 4.5%, p=0.0425) and the physiologically normal cut-off (12.3% vs 4.5%, p=0.0200). Exploratory analyses linked antibody levels to triglyceride-related profiles.
Assay-specific 99th-percentile reference intervals for aCL IgAGM and anti-β2GPI IgAGM were established in a large health-inspection population and a physiologically normal reference subgroup. These findings provide a practical interpretive framework for combined-isotype assays and support future disease-oriented evaluation.
Authors
Sun Sun, Tao Tao, Gong Gong, Wang Wang, Gao Gao, Zhang Zhang, Liang Liang, Sun Sun
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