Full biomarker guide
OmegaCheck measures red blood cell fatty acids to score your omega-3 status and omega-6 to 3 balance. Order direct and test at a local Quest lab.
OmegaCheck is a blood test that looks at the types of fats (fatty acids) built into your red blood cell membranes. Because red blood cells live for about 3–4 months, the results tend to reflect your longer-term omega-3 intake and metabolism rather than what you ate yesterday.
If you have ever wondered whether your fish intake or omega-3 supplement is “doing anything,” this test gives you a measurable way to track progress. It also helps translate confusing terms like “omega-3 index” and “omega-6 to omega-3 ratio” into numbers you can trend over time.
Your result is not a diagnosis by itself. It is a nutrition and risk-context marker that is most useful when you interpret it alongside your overall diet, medications, and cardiometabolic labs (like lipids).
Do I need a OmegaCheck test?
You might consider OmegaCheck if you are trying to optimize omega-3 status for heart health, inflammation-aware nutrition, or athletic recovery, and you want something more objective than counting fish servings. It can also be useful if you avoid seafood, follow a plant-forward diet, or have a history of high triglycerides and want to know whether omega-3 intake is likely adequate.
Testing is especially practical when you are already taking an omega-3 supplement but are unsure about dose, consistency, or absorption. Many people take a capsule “most days” and assume their omega-3 status is high, but red blood cell fatty acids can still come back lower than expected.
You may also want this test if you are trying to shift the balance between omega-6 fats (common in many processed foods and seed oils) and omega-3 fats (EPA and DHA from fish or algae). OmegaCheck gives you multiple ratios that can help you see whether your overall pattern is moving in the direction you intended.
If you are using results to guide changes, it helps to review them with a clinician, dietitian, or PocketMD-style interpretation so you do not overreact to a single number or ignore other health priorities.
OmegaCheck is a laboratory-developed fatty acid profile performed in a CLIA-certified lab; results support risk and nutrition discussions but do not diagnose disease on their own.
Lab testing
Order labs to measure Omega-3 Index
from $50.49 at Quest Diagnostics
About 1 week
Schedule online — results typically within a week
Clear next steps
Guidance included, with follow-up care available
HSA / FSA
Eligible for pre-tax health spending accounts
Get this test with Vitals Vault
With Vitals Vault, you can order OmegaCheck for yourself and complete the blood draw at a local Quest location. This is helpful when you want to measure your baseline, make a targeted diet or supplement change, and then retest to confirm your plan is working.
After your results post, PocketMD can help you translate the report into practical next steps, such as how to think about EPA+DHA intake, how to interpret omega-6 to omega-3 balance, and when it makes sense to pair your OmegaCheck trend with cardiometabolic markers like a lipid panel.
If your goal is heart-focused tracking, many people also add a companion lipid-focused check-in so you can see whether changes in fatty acids align with changes in triglycerides and other lipid markers over time.
- Order online and draw at a local Quest lab
- Designed for trending: baseline → change → retest
- PocketMD helps you interpret indices and ratios in plain language
Key benefits of OmegaCheck testing
- Shows your longer-term omega-3 status using red blood cell fatty acids rather than a single-day snapshot.
- Reports the Omega-3 Index (EPA+DHA) so you can track whether intake is likely in a heart-supportive range.
- Highlights omega-6 to omega-3 balance, which can guide food choices beyond simply “take fish oil.”
- Includes ratios like AA/EPA that help you understand inflammatory balance signals in context.
- Helps you personalize dosing by showing whether your current fish or algae intake is moving the needle.
- Supports smarter retesting timelines (often after 8–16 weeks of consistent changes) because RBCs turn over slowly.
- Pairs well with lipid testing so you can connect fatty acid patterns with triglycerides and overall cardiometabolic goals.
What is OmegaCheck?
OmegaCheck is a red blood cell (RBC) fatty acid test. It measures the percentage of specific fatty acids in your RBC membranes, including key omega-3 fats (EPA and DHA) and omega-6 fats (like linoleic acid and arachidonic acid). Results are typically reported as percentages of total identified fatty acids, plus calculated indices and ratios.
Because RBC membranes reflect dietary intake and metabolism over the lifespan of the cell, OmegaCheck is often used as a “medium-term” marker of fatty acid status. That makes it different from plasma fatty acids, which can swing more with recent meals.
The headline number many people look for is the Omega-3 Index, which is the combined percentage of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) in RBCs. The report commonly includes additional ratios, such as omega-6 to omega-3 and AA/EPA (arachidonic acid to EPA), which can help you see whether your overall fat pattern is skewed toward omega-6 dominance.
OmegaCheck does not tell you the “perfect” supplement dose by itself. It tells you where you are now, and it gives you a way to confirm whether a consistent nutrition plan is producing the change you expected.
Why red blood cells are used
Red blood cells circulate for roughly 120 days, and their membranes incorporate fatty acids over time. That is why an RBC-based omega-3 index is often used to reflect habitual intake and tissue availability rather than short-term fluctuations.
What the main indices try to capture
The Omega-3 Index focuses on EPA+DHA, the long-chain omega-3s most associated with cardiometabolic research. The omega-6 to omega-3 ratio and AA/EPA ratio are pattern markers that can move with both increasing omega-3 intake and decreasing excess omega-6 intake.
What do my OmegaCheck results mean?
Low Omega-3 Index / low EPA+DHA
A low Omega-3 Index generally means your longer-term intake or incorporation of EPA and DHA is low. This is common if you rarely eat fatty fish, rely only on ALA sources (like flax or chia), or take an omega-3 supplement inconsistently. If you are making changes, the most useful next step is usually to pick one clear strategy (more fatty fish, algae-based DHA/EPA, or a consistent fish oil dose) and plan a retest after you have been steady for several months.
In-range (or improving) omega-3 status
An in-range or improving Omega-3 Index suggests your current pattern is supplying EPA and DHA at a level that is showing up in RBC membranes. If your ratios (omega-6 to omega-3 and AA/EPA) are also moving in a favorable direction, that is a sign your overall fat balance is shifting, not just one nutrient. This is a good time to focus on consistency and to connect the result with your goals, such as triglyceride trends, blood pressure, or training recovery.
High Omega-3 Index / high EPA+DHA
A higher Omega-3 Index often reflects regular fatty fish intake or higher-dose supplementation. For many people, that is intentional, but “higher” is not automatically “better” for every situation, especially if you are also using medications or supplements that affect bleeding risk. If your value is high, it is reasonable to review your total omega-3 dose, your full medication list, and whether you have symptoms like easy bruising, and then decide with a clinician whether to maintain or adjust.
Factors that influence OmegaCheck
Your results can shift with seafood intake, supplement type (fish vs algae), dose, and how consistently you take it. Metabolic factors such as body size, triglyceride levels, insulin resistance patterns, and genetic differences in fatty acid handling can also affect how much EPA and DHA show up in RBCs. Recent major diet changes, weight loss, or changes in alcohol intake can alter lipid metabolism and may change your ratios over time. Finally, lab-to-lab reference ranges can vary, so it helps to trend your results with the same method when possible.
What’s included
- Epa+Dpa+Dha
- Arachidonic Acid/Epa Ratio
- Omega-6/Omega-3 Ratio
- Omega-3 Total
- Epa
- Dpa
- Dha
- Omega-6 Total
- Arachidonic Acid
- Linoleic Acid
Similar tests to consider
Frequently Asked Questions
Do I need to fast for an OmegaCheck test?
Often you do not need to fast because the test is based on red blood cell fatty acids, which are less sensitive to a single meal than plasma fats. However, if you are drawing other labs at the same time (like a lipid panel or glucose/insulin), fasting instructions may apply to the combined order. Follow the collection instructions on your lab order.
How long does it take for the Omega-3 Index to change?
Because red blood cells turn over slowly, meaningful changes usually take weeks to months. Many people retest after about 8–16 weeks of consistent intake changes to see a clear shift, although the best timing depends on how big the change was and how consistent you have been.
What is a good Omega-3 Index?
Labs may use different reference ranges, and “good” depends on your health goals and overall risk profile. In general, a higher Omega-3 Index reflects more EPA+DHA in red blood cells, but you should interpret the number alongside your ratios, your lipid markers, and your medication/supplement context rather than chasing a single target.
Is OmegaCheck the same as an omega-6 to omega-3 ratio test?
OmegaCheck typically includes the omega-6 to omega-3 ratio, but it also reports the Omega-3 Index (EPA+DHA) and individual fatty acids like EPA, DHA, and arachidonic acid. The ratio can improve either by increasing omega-3 intake, decreasing excess omega-6 intake, or both, so having the full profile can make your next steps clearer.
Can I use OmegaCheck to decide how much fish oil to take?
It can help you personalize dosing by showing whether your current routine is raising EPA and DHA in red blood cells. The test does not set a universal “right dose,” and your ideal approach depends on diet, goals, tolerability, and medical factors (including medications that affect bleeding). If you adjust dose, plan to retest after a consistent period to confirm the effect.
What can cause a low Omega-3 Index even if I take supplements?
Common reasons include inconsistent use, a lower EPA/DHA dose than you think, taking a product with less EPA/DHA per serving, or stopping and starting frequently. Some people also incorporate omega-3s differently due to metabolic factors, higher triglycerides, or body size, which can mean you need a more consistent plan and a longer retest window to see change.
Should I pair OmegaCheck with other labs?
If your goal is cardiovascular tracking, pairing OmegaCheck with lipid markers (such as triglycerides and other cholesterol measures) can help you connect fatty acid changes with cardiometabolic outcomes. If your goal is inflammation-aware nutrition, it can also be useful to review overall diet quality and any clinician-recommended inflammatory markers rather than relying on fatty acid ratios alone.
How does ordering Omega-3 Index work?
Purchase online through Vitals Vault. A licensed clinician reviews and approves your order, then you receive a digital requisition for a Quest Diagnostics blood draw.
Where do I get my blood drawn?
Samples are collected in person at Quest Diagnostics locations nationwide. After checkout you can schedule your visit at a convenient site.
How long until I get results?
Most results are ready about a week after your draw. You can view them securely in your Vitals Vault account.
Do I need a doctor referral?
No separate referral appointment is required. Clinician review is included in the online order flow.
Are HSA and FSA accepted?
Yes. Eligible HSA/FSA cards can be used at checkout for qualifying lab orders.
Are my results private?
Results are available in your secure Vitals Vault account. You control who you share them with, subject to applicable law.
What is the difference between blood glucose and A1c?
Blood glucose shows the amount of sugar in your blood at a single moment. A1c (hemoglobin A1c) estimates your average blood sugar over roughly the past 8–12 weeks. Comparing them helps explain whether your long-term average lines up with your fasting glucose on draw day.
What does Omega-3 Index help me understand?
It helps you understand how this marker fits into your broader metabolic picture, with results tracked in your Vitals Vault account.
What can I do if my A1c or glucose results are elevated?
Elevated values can signal higher metabolic risk. Many people start with nutrition, activity, sleep, and weight management, then retest and review results with a clinician. This test is educational and does not replace medical advice or diagnosis.
How accurate is this testing?
Your sample is processed at CLIA-certified Quest Diagnostics laboratories. Results should still be interpreted with a qualified clinician alongside your history, symptoms, and other labs.
Why is there an age minimum for ordering?
Consumer-initiated testing through Vitals Vault is limited to adults 18+ so ordering and interpretation stay aligned with clinical best practices for this channel.
