Is Omega-3 Index useful for allergy?

The Omega-3 Index measures EPA and DHA in red blood cell membranes and is primarily validated for cardiovascular risk assessment. For allergies, the evidence is limited: some observational studies and small RCTs suggest a possible link between higher omega-3 levels and reduced allergic symptoms (e.g., hay fever, asthma), especially in children. The anti-inflammatory mechanisms of EPA/DHA are plausible, but the Omega-3 Index as a specific allergy biomarker is not established. It may be useful as part of a broader inflammatory assessment, but it does not replace allergy testing. Caveat: the index is highly diet-dependent; an optimal range for allergies is undefined. Evidence grade: human-moderate.