Omega-3 Index optimal range and reference range

Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026

Sera's bands for Omega-3 Index:

Optimal 8 – 12 %; sufficient 4 – 8 %; out of range below 4 or above 12 %.

Evidence grade: Functional / longevity target. A narrower target in common use in functional, integrative, preventive and longevity practice. It is not a universally validated diagnostic range.

All units

Unit	Optimal	Sufficient	Out of range
%	8 – 12	4 – 8	below 4 or above 12

What the evidence says

The best-evidenced marker in this area. Harris and von Schacky proposed red cell EPA plus DHA as a risk marker, with 8 to 12% the low-risk zone and below 4% high risk. A 2017 analysis of 10 cohorts estimated about 30% lower risk of fatal coronary disease at 8% than at 4%, and Canada's national health survey uses the same two cut-points. Average levels in the United States, Canada, Germany and Italy are 4.5 to 5.8%, so a Sufficient result is the usual finding. Observational, though: no trial has shown that raising the Index to a target changes outcome, which is why this is a functional target rather than an established threshold. The 12% upper edge is the top of the proposed target range, not a level shown to cause harm. Not interchangeable between laboratories: small differences in analytical method give large differences in the Index, and the published cut-offs belong to the original standardised method, so a result from another method should not be read against them as if it were the same test.

Sources

The Omega-3 Index and relative risk for coronary heart disease mortality: Estimation from 10 cohort studies — Harris WS, Del Gobbo L, Tintle NL — Atherosclerosis, 2017 · Peer-reviewed publicationTests the originally proposed cut-points of below 4% (higher risk) and 8 to 12% (lower risk) in 10 cohorts. Mean Index 6.1%; fatal coronary risk is estimated about 30% lower at 8% than at 4%, and the authors conclude that below 4% and above 8% are reasonable targets. This matches Sera's 4, 8 and 12.
Proportions of long-chain ω-3 fatty acids in erythrocyte membranes of Canadian adults: Results from the Canadian Health Measures Survey 2012-2015 — Demonty I, Langlois K, Greene-Finestone LS, Zoka R, Nguyen L — The American Journal of Clinical Nutrition, 2021 · Peer-reviewed publicationNationally representative Canadian survey (4,025 adults) that classifies an Omega-3 Index below 4% as undesirable and names 8% or above as the currently proposed target. Mean Index 4.5%; almost 40% of Canadians were below 4%. Matches Sera's 4 and 8.
Erythrocyte long-chain omega-3 fatty acid levels are inversely associated with mortality and with incident cardiovascular disease: The Framingham Heart Study — Harris WS, Tintle NL, Etherton MR, Vasan RS — Journal of Clinical Lipidology, 2018 · Peer-reviewed publicationFramingham Offspring cohort, 2,500 people followed 7.3 years: those with an Omega-3 Index above 6.8% had a 34% lower risk of death from any cause and 39% lower risk of cardiovascular disease than those below 4.2%. Supports the direction of the 4 to 8% gradient; the quintile cut-points are not Sera's edges.
Red Blood Cell Fatty Acid Patterns from 7 countries: Focus on the Omega-3 Index — Schuchardt JP, Cerrato M, Ceseri M, et al. — Prostaglandins, Leukotrienes and Essential Fatty Acids, 2022 · Peer-reviewed publicationStates the Omega-3 Index categories used in the field: desirable above 8%, moderate above 6 to 8%, low above 4 to 6%, very low 4% or below. Mean Index in the United States, Canada, Italy and Germany was 4.5 to 5.8%, so most Western clients will score Sufficient, not Optimal.
Omega-3 index in 2018/19 — von Schacky C — The Proceedings of the Nutrition Society, 2020 · Peer-reviewed publicationStates that even small differences in analytical methods give large differences in Omega-3 Index results, and that results are often read against the 8 to 11% target defined for the original validated method. The author founded the company behind that method.

What Omega-3 Index measures

The share of EPA and DHA, two omega-3 fats, in your red blood cell membranes.

A level above 8% points to an anti-inflammatory, heart-protective state. A low level below 4% encourages inflammation.

Related fatty acids markers

See Omega-3 Index in the full list of biomarker ranges

This page is a reference for practitioners, not medical advice. Sera's bands are practitioner targets for structured review, not diagnostic thresholds, and Sera does not diagnose or recommend treatment. Read a result alongside the interval printed by the issuing laboratory and the client's history and symptoms. Range set: Sera Production, version 1.0, last reviewed November 9, 2026.