Indicator Explainer
CD3 Complex
A protein complex comprised of one T-cell surface glycoprotein CD3 delta chain (CD3D), one T-cell surface glycoprotein CD3 gamma chain (CD3G) and two T-cell surface glycoprotein CD3 epsilon chains (CD3E). CD3D, CD3G and CD3E are transmembrane proteins with one extracellular immunoglobulin domain and one intracellular ITAM domain. The CD3 complex is a T-cell co-receptor that noncovalently associates with either the disulfide bound heterodimeric alpha/beta T-cell receptor (TCR) or gamma/delta TCR and two copies of the accessory protein, T-cell surface glycoprotein CD3 zeta chain (CD247), which is a transmembrane protein with three ITAM domains. The TCR moiety of the TCR-CD3 complex binds to MHC and processed antigens on antigen presenting cells, which triggers phosphorylation of and cellular propagation of the signal by CD247 and the CD3 complex.
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, C38897. NCI definition, reproduced without modification under CC BY 4.0. Source identity and definition checked automatically on 2026-10-20. 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.