The Omega-3 Index

The American Heart Association reports that coronary heart disease (CHD) is the number one killer of American men and women, accounting for more than one of every five deaths in the United States, usually as sudden death from cardiac arrest. Unfortunately, about 95% of sudden cardiac arrest victims die before reaching the hospital.


Researchers have discovered that one of the best risk indicators for sudden cardiac death is the level of omega-3 fatty acids (EPA and DHA) found in red blood cell membranes. Now there is a reliable omega-3 blood test— the Omega-3 Index —that is simple to use and cost effective that allows you to monitor and manage your own omega-3 status.




On August 7, 2008, Dr. Bernadine Healy, the health writer for US News and World Report and past director of the NIH and past President of the American Heart Association, published a column entitled, “From Fish Oil to Medicine.” She opened with the following:

With all the talk about fat being bad—whether it’s on our bodies or in our diet—we have failed to take seriously a significant nutritional fat deficiency that afflicts most Americans: We have too little omega-3s of the kind found in oily fish, which cannot be made by the human body yet are essential to metabolism. Even though we need only a small dose, our western diet runs woefully low, forcing our cells to run their engines slightly off balance. Over time, this takes its toll. The deficiency significantly increases the risk of heart attacks and sudden cardiac death, and mounting evidence suggests omega-3 shortages contribute to problems as disparate as premature birth, neurological disorders, mental illness, autoimmune disease, obesity, and certain cancers. This is no fish story: Raising omega-3s could be as important to public health as lowering cholesterol.


In her column, Dr. Healy quoted William Harris, PhD, an international expert on omega-3’s, who said, “Based on what we currently know there is no nutrient more important for decreasing risk of cardiovascular death—and more lacking—than omega-3.” Dr. Harris is currently a Professor in the Department of Internal Medicine at the Sanford USD School of Medicine, in Sioux Falls, SD. He is also the President of OmegaQuant Analytics, LLC (also in Sioux Falls) and a Senior Research Scientist at Health Diagnostic Laboratory, Inc., in Richmond, VA.

The primary purpose of Dr. Healy’s column was to highlight a new blood test for a new cardiovascular risk factor: red blood cell omega-3 levels. She concluded with a look into the future: “Before long, your personal omega-3 index just could be the new cholesterol—the number you want to brag about.”


A New Test Introduced


The new test that Dr. Healy was referring to is called the Omega-3 Index and was developed by Dr. Harris and his colleague, Clemens von Schacky, MD, a cardiologist in Munich, Germany. Their seminal 2004 article introduced the concept of the omega-3 index. Below are some frequently asked questions about omega-3 fatty acids and this new blood test.


What Are Omega-3 Fatty Acids and Where Are They Found?

Omega-3 fatty acids are essential fatty acids in the human diet that are primarily found in oily fish like salmon, sardines, albacore tuna, herring, mackerel, etc. They are also available in fish oil capsules. The principle omega-3 fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). A more rudimentary form of omega-3 is found in soybean oil, canola oil, and especially in flaxseed oil. It is called alpha-linolenic acid (ALA), but unlike EPA and DHA, it has not yet been shown to have cardiovascular benefits. In other words, flaxseed oil is not a substitute for fish oil.


What Is the Evidence That Omega-3 Oils Are Cardioprotective?

Over the last 25 years, compelling evidence has accumulated from population studies and large clinical trials demonstrating the cardioprotective effects of omega-3 oils. The strongest evidence to date relates to reducing risk for sudden cardiac death (SCD), the primary cause of CHD death in the US today. There is also good evidence that higher Omega-3 Index levels are associated with slower cellular aging, improved brain function, lower levels of depression and reduced inflammation.


What Does the American Heart Association Say About Omega-3?

Patients with documented CHD should consume about 1 g of EPA+DHA per day, and those without documented CHD should eat a variety of fish, preferably oily, at least twice a week. The latter would provide about 500 mg of EPA+DHA per day.


How Can You Know If You Are Getting Enough Omega-3?

Measure your Omega-3 Index! This standardized blood test measures the content of EPA+DHA in red blood cell membranes and is expressed as a percent of total fatty acids in the membrane that are EPA+DHA. The Omega-3 Index is a valid reflection of cardiac omega-3 levels, and it is similar in concept to hemoglobin A1c – just as the latter is a measure of average blood glucose levels, the Omega-3 Index provides a long term assessment of tissue omega-3 levels.


What Is the Target Range For the Omega-3 Index?

The target Omega-3 Index is 8% and above, a level that current research indicates is associated with the lowest risk* for death from CHD. On the other hand, an Index of 4% or less (which is common in the US) indicates the highest risk*. Women tend to have slightly higher omega-3 levels during the childbearing years, and the Omega-3 Index actually rises with age, peaking out in the 70s.


*In this context, “risk” refers only to that associated with differing levels of omega-3 fatty acids. Risks associated with other factors such as cholesterol, blood pressure, diabetes, family history of CHD, smoking, or other cardiac conditions are completely independent of and not influenced by omega-3 fatty acids. All risk factors – including the Omega-3 Index—should be addressed as part of any global risk reduction strategy.


What Can You Do to Correct Your Omega-3 Index?

If your Omega-3 Index is in the high risk zone (<4%), you should increase your intake of EPA+DHA by about 2,000-3,000 mg/day; if it is in the intermediate zone, (4% to 8%), you should increase your EPA+DHA intake by about 500-1,000 mg/day. Either of these can be accomplished by eating more oily fish or by taking fish oil supplements. You should wait 4-6 months after changing your omega-3 intake before re-testing your Omega-3 Index in order to allow your system time to reach a new steady state.


Who Offers the Omega-3 Index Test?

The test is available for researchers and consumers from OmegaQuant Analytics, and for patients under a doctor’s care, through Health Diagnostic Laboratory.


How Do You Order the Test?

The test can be ordered directly from the OmegaQuant website.


What Does the Omega-3 Index Test Cost?

The test costs $35 (plus $5 shipping and handling). Other tests offered by OmegaQuant Analytics include the Trans Fat Index test and the Mother’s Milk DHA test, both of which are described on the website.

Once payment is made online, a dried blood (or milk) spot collection kit will be mailed to the client, who will collect a sample and mail it back to the laboratory.


How Quickly Will the Results Be Available?

Once sample is received in the lab, the results will be available online within 3 working days. Typically, you should receive your results within 1 week of mailing in the sample.


Why Not Just Skip the Test and Eat More Fish or Take Supplements?

Although strongly correlated with the EPA+DHA intake, the exact value for the Omega-3 Index cannot be predicted from just knowing the omega-3 intake. There is considerable person-to-person variability and it is very difficult to know the actual amount of omega-3 consumed in the diet, particularly if relying on fish as the source. This is because omega-3 levels vary by season, by location of the catch, and by preparation method so that the specific amount in a particular serving of fish is unknown. We measure lipid levels even when people are on lipid-lowering drugs; the same logic applies to omega-3.



The Omega-3 Index has been shown to be a better indicator of relative risk for sudden cardiac death than other CHD risk factors. At the highest omega-3 level, this risk is reduced by 90%. A higher Omega-3 Index has been linked with improved cognitive function and less inflammation, so it does not just correspond to risk for heart disease. Low omega-3 levels are easily corrected through dietary changes or supplements and can quickly improve test results. The test is inexpensive, and the sample can be easily collected at home. Achieving an optimal Omega-3 Index may be one of the best things you can do to reduce your risk for heart attacks and other diseases of aging.




Harris WS. Fish oil supplementation: evidence for health benefits. Cleve Clin J Med 2004; 71:208.

Kris-Etherton PM, Harris WS, Appel LJ. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation 2002; 106:2747-2757.

Harris WS, Sands SA, Windsor SL, Ali HA, Stevens TL, Magalski A et al. Omega-3 Fatty Acids in Cardiac Biopsies from Heart Transplant Patients: Correlation with Erythrocytes and Response to Supplementation. Circulation 2004; 110:1645-1649.

Harris WS, von Schacky C. The Omega-3 Index: a new risk factor for death from coronary heart disease? Prev Med 2004; 39:212-220.

Block RC, Harris WS, Reid KJ, Sands SA, Spertus JA. EPA and DHA in Blood Cell Membranes from Acute Coronary Syndrome Patients and Controls. Atherosclerosis 2007; 197:821-828.

Block RC, Harris WS, Pottala JV. Determinants of Blood Cell Omega-3 Fatty Acid Content. Open Biomarkers J 1, 1-6. 2008.

Siscovick DS, Raghunathan TE, King I, Weinmann S, Wicklund KG, Albright J et al. Dietary intake and cell membrane levels of long-chain n-3 polyunsaturated fatty acids and the risk of primary cardiac arrest. J Am Med Assoc 1995; 274:1363-1367.

Albert CM, Campos H, Stampfer MJ, Ridker PM, Manson JE, Willett WC et al. Blood levels of long-chain n-3 fatty acids and the risk of sudden death. N Engl J Med 2002; 346:1113-1118.

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