Indicator Explainer
IgM
The major immunoglobulin secreted during a primary immune response. IgM binds with low affinity but high avidity (multiple binding sites) because it not only occurs as monomers but also as pentamers and hexamers.
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, C569. 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 — IgM (C569)
- Source: National Cancer Institute, NCI Thesaurus 26.09d, C569. NCI definition, reproduced without modification under CC BY 4.0.
- An evaluation of the performance and usability of a measles IgM rapid diagnostic test within the Uganda national surveillance program using capillary blood and oral fluid samples. — Epidemiol Infect, 2026-10-14 (PMID 42872506; literature)
- Antigen-independent BCR signals limit differentiation and survival of IgM antibody-secreting cells. — J Exp Med, 2026-10-22 (PMID 42911265; literature)
- Determining an Optical Density (OD) cut-off value of IgM Enzyme-Linked Immunosorbent Assay (ELISA) for the diagnosis of Scrub typhus in the selected states of Northeast India. — Indian J Med Microbiol, 2026-10-21 (PMID 42906691; literature)
- Immunopathogenetic Features of Measles in Adults: Association of Vaccination Status with Measles-Specific IgM Levels and Cytokine Profile (IL-1β, IL-10). — Infect Drug Resist, 2026-10-21 (PMID 42935665; literature)