omega-3 index
The percentage of EPA and DHA fatty acids in red blood cell membranes, used as a biomarker of omega-3 status.
Full Definition
The omega-3 index represents the combined percentage of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in red blood cell membranes, expressed as a percentage of total fatty acids. This biomarker reflects longer-term omega-3 fatty acid status compared to plasma levels, as red blood cells have a lifespan of approximately 120 days. Target levels for cardiovascular protection are generally considered to be ≥8%, with levels <4% associated with increased cardiovascular risk. The omega-3 index is measured using standardized analytical methods and provides objective assessment of omega-3 status independent of dietary recall. This measurement helps guide omega-3 supplementation decisions and monitor therapeutic response.
Usage
Usage note: Express as percentage; distinguish from plasma levels which reflect short-term status.
In Context
- "The patient's omega-3 index of 3.2% indicated suboptimal omega-3 status requiring supplementation." — Nutritional assessment report
- "Follow-up testing showed improvement in omega-3 index from 4.1% to 7.8% after six months of supplementation." — Therapeutic monitoring note