Omega-3 Index
The percentage of EPA and DHA in red blood cell membranes, reflecting long-term omega-3 intake.
| Typical reference range | above 4 % |
| Commonly cited optimal range | above 8 % |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
The omega-3 index measures EPA and DHA as a percentage of total fatty acids in red cell membranes. Because red cells live about 120 days, it reflects average intake over several months.
Why it matters
Higher omega-3 index values are associated with lower risk of fatal heart disease and sudden cardiac death; above 8% is considered desirable and below 4% higher risk. Most people eating a typical Western diet are in the 4-6% range.
What a high result can mean
High values reflect regular fatty fish consumption or omega-3 supplements and are generally favorable; very high intakes can increase bleeding tendency and possibly atrial fibrillation risk in some people.
What a low result can mean
Low values reflect low intake of fatty fish or omega-3 supplements; genetics and smoking also lower it.
What affects the result
No fasting required. Changes take 3-4 months to stabilize after altering intake. Quest's OmegaCheck reports EPA+DPA+DHA as a percentage of whole-blood fatty acids, which has different cut-offs (above 5.4% desirable) than the RBC-based omega-3 index.
Unit
Usually reported in %.
Also called on lab reports
Omega 3 Index, OmegaCheck, Omega-3 Total, Omega-3 (EPA+DPA+DHA), Omega-3 Index (EPA+DHA), Omega-3 Fatty Acids, Total
Related tests: Vitamins & Nutrients
This page is educational and does not replace advice from a healthcare professional.