Indicator Explainer
Homocysteine
An amino acid derivative and homolog of cysteine containing an additional methylene bridge. Homocysteine is a product of methionine metabolism and elevated plasma levels are associated with cardiovascular disease, Alzheimer disease and several metabolic diseases.
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, C105949. NCI definition, reproduced without modification under CC BY 4.0. Source identity and definition checked automatically on 2026-10-19. 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 — Homocysteine (C105949)
- Source: National Cancer Institute, NCI Thesaurus 26.09d, C105949. NCI definition, reproduced without modification under CC BY 4.0.
- Homocysteine as a Key Biomarker of Metabolic Stress During Foslevodopa/Foscarbidopa Infusion Therapy. — Mov Disord, 2026-09-23 (PMID 42778394; literature)
- Season of sampling and the interpretation of serum homocysteine results: a within-person analysis of 268,877 health-screening examinations. — Clin Chem Lab Med, 2026-09-23 (PMID 42770710; literature)
- An organotellurium-based BOPHY system for discrimination of homocysteine over cysteine. — Chem Commun (Camb), 2026-10-15 (PMID 42879250; literature)
- Association of Admission Serum Homocysteine with Discharge Neurocognitive Dysfunction after Acute Cerebrovascular Disease in a High-Altitude Setting. — J Vis Exp, 2026-10-16 (PMID 42891598; literature)
- The Effect of Bariatric Surgery on Homocysteine Levels: A Meta-analysis. — Surg Laparosc Endosc Percutan Tech, 2026-10-26 (PMID 42932860; literature)
- Simultaneous Quantification of Total Homocysteine and Methylmalonic Acid by LC-MS/MS for Comprehensive Assessment of Vitamin B12 and Folate deficiencies. — Biochimie, 2026-10-22 (PMID 42913996; literature)