Indicator Explainer
Histidine
A semi-essential amino acid (children should obtain it from food) needed in humans for growth and tissue repair, Histidine is important for maintenance of myelin sheaths that protect nerve cells and is metabolized to the neurotransmitter histamine. Histamines play many roles in immunity, gastric secretion, and sexual functions. Histidine is also required for blood cell manufacture and protects tissues against damage caused by radiation and heavy metals. (NCI04)
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, C29597. 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.