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.

Reviewed 2026-10-18

Read this first

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

IgAImmunoglobulin A

When it is tested

Reading results

Also Known As

References