Omega-3 Index

Omega-3 Index (erythrocyte EPA + DHA), also known as the omega-3 polyunsaturated fatty acids index or n-3 fatty acid biomarker, is used to assess cardiovascular risk, including susceptibility to arrhythmias and sudden cardiac death. The test supports evaluation for omega-3 fatty acid deficiency and is used to monitor omega-3 intake during dietary changes or supplementation programs.

Omega-3 polyunsaturated fatty acids are essential nutrients with cardioprotective, lipid-lowering, and antiarrhythmic effects. They also participate in processes such as cell division and growth, digestion, coagulation, brain function, and intracellular transport. The omega-3 index is calculated as the sum of EPA and DHA expressed as a percentage of total fatty acids in the erythrocyte membrane, and it tracks habitual intake of these fatty acids. Lower omega-3 index values are linked to increased cardiovascular risk, with a particularly strong association with sudden cardiac death. EPA and DHA are primarily obtained from fatty fish (eg, salmon, tuna, mackerel, herring) and certain marine algae. Alpha-linolenic acid from plant sources undergoes only partial conversion to EPA and DHA. Maintaining an adequate omega-3 status, as reflected by the omega-3 index, is one element of comprehensive cardiovascular risk reduction.