Test Summary
OmegaCheck®
Test code: 92701
Clinical use
- Determine fatty acid-associated risk for cardiovascular events
Clinical background
Diets rich in omega-3 polyunsaturated fatty acids (PUFAs) are beneficial for heart health and may reduce the risk of cardiovascular disease (CVD) and events (eg, myocardial infarction [MI]).1 However, dietary intake of omega-3 PUFAs and/or supplements does not strongly correlate with their concentrations in the body because of interindividual differences in genetics and metabolism.2-4 Individuals with the same dietary intake can have different concentrations of omega-3 PUFAs.2-4 Consequently, blood testing is needed to assess whether an individual's omega-3 PUFA levels are sufficient to achieve a reduction in CVD risk.3,4
Specimen type also influences the results for different PUFAs obtained through blood testing; based on literature reports, biological variability has been assessed as highest in plasma, lowest in red blood cells, intermediate in whole blood, and unknown in serum.5 The major omega-3 PUFAs that are measured include eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and docosapentaenoic acid (DPA), which is an intermediate metabolite formed during the interconversion of EPA and DHA. Alpha-linolenic acid is another major omega-3 PUFA but is metabolized to EPA2,6 and does not substantially contribute to omega-3 blood levels.3
Higher levels of EPA are associated with a lower risk of cardiovascular events (eg, MI). Clinical trials have shown that elevating combined EPA and DHA levels leads to reductions in triglyceride levels.7 A pooled meta-analysis indicated that patients with high (versus low) total circulating levels of EPA, DHA, and DPA—a sum used in calculating the risk for CVD—were at reduced risk of sudden cardiac death by 45%.8
The OmegaCheck® test (test code 92701) offered by Quest Diagnostics and Cleveland HeartLab is a method for measuring omega-3 PUFAs in whole blood, assessing the risk of CVD, and determining whether intake of fatty acids is achieving therapeutic goals. The OmegaCheck test uses the sum of EPA, DHA, and DPA expressed as a percentage of total fatty acids.9 OmegaCheck and the sum of EPA and DHA in red blood cells (also called the Omega-3 index) are highly correlated (r=0.91)10 values and are used as indicators for sudden cardiac death9 and nonfatal cardiovascular events.
Individuals suitable for testing
- Individuals at high risk of cardiovascular disease, especially those with hypertriglyceridemia
Method
- LC/MS/MS measurement
- omega-3 fatty acids: EPA, DHA, and DPA
- omega-6 fatty acids: linoleic acid (LA) and arachidonic acid (AA), which are reported as a percentage of total fatty acids (PLFAs); total PLFA measurement includes the 16 highest-concentration fatty acids (C14 through C22) present in plasma phospholipids
- Calculations
- OmegaCheck = [(EPA + DPA + DHA) ÷ total PLFA] x 100
- Omega-6/omega-3 = sum of 6 omega-6 fatty acids ÷ sum of 3 omega-3 fatty acids
- AA/EPA = % AA ÷ % EPA
- Analytical sensitivity
- EPA: 0.03%
- DHA: 0.03%
- DPA: 0.02%
Interpretive information
The CVD risks associated with OmegaCheck values are shown in the Table. Thresholds were established by stratifying data of the studied population into quartiles. Previous population-based studies have shown a dose-dependent decrease in CVD risk with increasing levels of omega-3 PUFAs. Relative to individuals in the highest quartile, individuals in the lowest quartile are at highest risk and those in the second and third quartiles (combined in the Table) are at moderate risk.11,12
Table. Interpretation of OmegaCheck Values
OmegaCheck value, % by weight |
Cardiovascular disease risk level |
≥5.5 |
Lowa |
3.8–5.4 |
Moderate |
≤3.7 |
High |
a Relative to those with lower OmegaCheck values.
Consumption of foods high in omega-3 fatty acids (EPA and DHA), dietary supplements containing omega-3 fatty acids, and prescription omega-3 fatty acids can increase the OmegaCheck value, which is associated with decreased CVD risk (Table).
A high omega-6/omega-3 ratio is associated with a higher risk of major coronary events but should be interpreted with caution because it does not differentiate fatty acids that have different physiological properties (eg, effect on platelet function and lowering triglycerides).10
A higher AA/EPA ratio is associated with higher risk for major coronary events (sudden cardiac death, fatal or nonfatal myocardial infarction, unstable angina pectoris with myocardial ischemia, or the need for revascularization procedures).12
References
- Kaur G, Mason RP, Steg PG, et al. Omega-3 fatty acids for cardiovascular event lowering. Eur J Prev Cardiol. 2024;31(8):1005-1014. doi:10.1093/eurjpc/zwae003
- Davinelli S, Intrieri M, Corbi G, et al. Metabolic indices of polyunsaturated fatty acids: current evidence, research controversies, and clinical utility. Crit Rev Food Sci Nutr. 2021;61(2):259-274. doi:10.1080/10408398.2020.1724871
- Harris WS, Tintle NL, Imamura F, et al. Blood n-3 fatty acid levels and total and cause-specific mortality from 17 prospective studies. Nat Commun. 2021;12(1):2329. doi:10.1038/s41467-021-22370-2
- Flock MR, Skulas-Ray AC, Harris WS, et al. Determinants of erythrocyte omega-3 fatty acid content in response to fish oil supplementation: a dose-response randomized controlled trial. J Am Heart Assoc. 2013;2(6):e000513. doi:10.1161/jaha.113.000513
- Schacky C von. Assessing omega-3 fatty acids–critically weighing options and relevance. J Clin Lipidol. 2025;19(2):208-214. doi:10.1016/j.jacl.2024.10.009
- Elagizi A, Lavie CJ, O'Keefe E, et al. An update on omega-3 polyunsaturated fatty acids and cardiovascular health. Nutrients. 2021;13(1):204. doi:10.3390/nu13010204
- Toth PP, Chapman MJ, Parhofer KG, et al. Differentiating EPA from EPA/DHA in cardiovascular risk reduction. Am Heart J Plus: Cardiol Res Pr. 2022;17:100148. doi:10.1016/j.ahjo.2022.100148
- Kim JY, Kong SYJ, Jung E, et al. Omega-3 fatty acids as potential predictors of sudden cardiac death and cardiovascular mortality: a systematic review and meta-analysis. J Clin Med. 2024;14(1):26. doi:10.3390/jcm14010026
- Albert CM, Campos H, Stampfer MJ, et al. Blood levels of long-chain n–3 fatty acids and the risk of sudden death. N Engl J Med. 2002;346(15):1113-1118. doi:10.1056/nejmoa012918
- Harris WS, Schacky C von. The Omega-3 Index: a new risk factor for death from coronary heart disease? Prev Med. 2004;39(1):212-220. doi:10.1016/j.ypmed.2004.02.030
- Siscovick DS, Raghunathan TE, King I, et al. Dietary intake and cell membrane levels of long-chain n-3 polyunsaturated fatty acids and the risk of primary cardiac arrest. JAMA. 1995;274(17):1363-1367. doi:10.1001/jama.1995.03530170043030
- Itakura H, Yokoyama M, Matsuzaki M, et al. Relationships between plasma fatty acid composition and coronary artery disease. J Atheroscler Thromb. 2011;18(2):99. doi:10.5551/jat.5876
Content reviewed 9/2025
92701 - OmegaCheck®
Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.
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