Indicator Explainer
IgA
IgA is the immunoglobulin subclass that is associated with antibody-mediated mucosal immunity. It is secreted as dimers into the mucosa and is the most effective isotype at fixing complement by the alternative pathway, even though it lacks the ability to fix complement by the classical pathway. There are two subtypes in the human - IgA1 and IgA2.
This page explains what the indicator is and how results are interpreted in general terms. Reference ranges depend on the laboratory, the method, and your own situation — no single “normal value” applies to everyone. This page is health information, not a diagnosis. For symptoms, treatment, or urgent concerns, contact a healthcare professional.
When it is tested
Source: National Cancer Institute, NCI Thesaurus 26.09d, C565. NCI definition, reproduced without modification under CC BY 4.0. Source identity and definition checked automatically on 2026-10-18. No individual clinical interpretation or human reviewer is asserted.
Reading results
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.
Also Known As
Related Tests
Tests that measure or involve this indicator.
References
- NCI Thesaurus 26.09d — IgA (C565)
- Source: National Cancer Institute, NCI Thesaurus 26.09d, C565. NCI definition, reproduced without modification under CC BY 4.0.
- Detection of MOG-IgG and MOG-IgA in Maternal Breast Milk and Infant Blood in MOGAD: A Case Report. — Neurol Neuroimmunol Neuroinflamm, 2026-10-09 (PMID 42854177; literature)
- Follicle-associated epithelial tuft cells amplify type 2 mucosal immunity and IgA production. — Sci Immunol, 2026-10-09 (PMID 42853963; literature)
- Targeted-Release Formulation Budesonide (Nefecon) for the Treatment of IgA Nephropathy in Three Adolescents. — Kidney360, 2026-10-08 (PMID 42848663; literature)
- Clinical and pathological factors associated with eGFR slope in IgA nephropathy: a single-center retrospective cohort study. — Ren Fail, 2026-10-07 (PMID 42844235; literature)
- Integrated analysis identifies dysregulated secretory proteins and crotonylation profiles associated with immune regulation in IgA nephropathy. — J Proteomics, 2026-10-07 (PMID 42843589; literature)
- Adult-onset IgA vasculitis with crescentic nephritis triggered by pulmonary tuberculosis: A case report. — Trop Doct, 2026-10-07 (PMID 42842753; literature)
- RealxWorld Effectiveness of Targeted-Release Budesonide in IgA Nephropathy with Near-Universal SGLT2 Inhibitor Use. — Am J Nephrol, 2026-10-15 (PMID 42879331; literature)
- Microangiopathic lesions associated with poor immunosuppressive therapy response in IgA nephropathy. — Nephrol Dial Transplant, 2026-10-15 (PMID 42878692; literature)
- Ravulizumab in IgA Nephropathy - Interim Analysis of a Phase 3 Trial. — N Engl J Med, 2026-10-23 (PMID 42912700; literature)
- Interim Analysis of a Phase 3 Trial of Povetacicept in IgA Nephropathy. — N Engl J Med, 2026-10-23 (PMID 42912669; literature)
- Disease-modifying antirheumatic drugs in childhood-onset IgA vasculitis: a large multicenter Latin American study. — Clinics (Sao Paulo), 2026-10-28 (PMID 42950687; literature)
- Association of airway CCL28 with type 2 inflammation and secretory IgA in patients with asthma. — PLoS One, 2026-10-28 (PMID 42949886; literature)