Indicator Explainer
Carboxyhemoglobin
Hemoglobin where the heme group has formed a stable complex with carbon monoxide (CO). This complex is produced after CO has been inhaled or as a byproduct of hemoglobin, protoporphyrin or dichloromethane catabolism. The heme-CO complex is approximately 200 times more stable than heme-oxygen complexes. Thus, high levels of carboxyhemoglobin in the circulation can lead to tissue hypoxia and death.
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, C114300. 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.