The Omega-3 Index
EPA and DHA are not absorbed and processed equally by all people. In addition to dietary influences, in particular quantity and composition of fats consumed as food, there also appears to be genetic factors at work. For this reason EPA/DHA requirements vary considerably by individual and may be higher than the intake levels nutritional organizations recommend.
Studies have shown that an HS-omega-3 Index of 8-11 is associated with a clearly positive impact on health.1 People in Western industrialized countries however often show values that are considerably lower.
1Harris: The omega-3 index: Clinical utility for therapeutic intervention (2010)