Arachidonic Acid/EPA Ratio Biomarker Testing
It shows your omega-6 to omega-3 balance in blood to help interpret inflammation risk; order and track results through Vitals Vault with Quest labs.
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The arachidonic acid/EPA ratio (often written AA/EPA) is a way to summarize how much omega-6 arachidonic acid you carry relative to the omega-3 fat eicosapentaenoic acid (EPA) in your blood.
Because these fats are building blocks for signaling molecules involved in inflammation and clotting, the ratio is often used as a “balance” marker. It does not diagnose a disease by itself, but it can help you and your clinician decide whether your diet, supplements, or cardiometabolic plan is moving in the direction you intended.
If you are already taking omega-3s, changing your diet, or tracking cardiovascular risk factors, this ratio can be especially useful as a trend over time rather than a one-time number.
Do I need a Arachidonic Acid/EPA Ratio test?
You might consider an AA/EPA ratio test if you are trying to understand whether your current eating pattern supports a healthier omega-6 to omega-3 balance. This comes up often when you are working on triglycerides, blood pressure, insulin resistance, or overall cardiovascular risk and you want a measurable way to track dietary changes.
Testing can also be helpful if you take fish oil or prescription omega-3s and you are not sure whether the dose is actually changing your blood fatty acid profile. Some people absorb or respond differently, and the ratio can show whether EPA is rising relative to arachidonic acid.
If you have chronic inflammatory conditions, joint pain, or frequent soreness after exercise, you may be curious about omega balance. The test cannot tell you the cause of symptoms, but it can add context for a clinician-directed plan.
If you are pregnant, on blood thinners, or have a bleeding disorder, discuss omega-3 dosing with your clinician. The lab result is one input and should not be used for self-diagnosis or medication changes on its own.
This is a laboratory measurement of blood fatty acids (often reported from red blood cell or whole-blood fractions) performed in CLIA-certified labs; results support clinical decision-making but are not a standalone diagnosis.
Lab testing
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from $134.47 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
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Get this test with Vitals Vault
With Vitals Vault, you can order an AA/EPA ratio test without a separate doctor visit and complete your blood draw through the Quest network. Your results are delivered in a clear format so you can focus on what changed and what to do next.
If you want help interpreting your ratio in context, PocketMD can walk you through common patterns and the most useful companion labs to review alongside it, such as triglycerides, A1c, or broader fatty acid markers.
This test is especially valuable when you repeat it after a consistent period of diet or omega-3 changes. Vitals Vault makes it easy to recheck and compare trends over time so you can avoid guessing.
- Order online and draw at Quest locations
- PocketMD support for next-step questions
- Designed for retesting and trend tracking
Key benefits of Arachidonic Acid/EPA Ratio testing
- Shows your omega-6 (arachidonic acid) to omega-3 (EPA) balance in a single, easy-to-track number.
- Helps you see whether omega-3 intake is meaningfully raising EPA in your blood, not just on a label.
- Adds context to cardiometabolic goals by pairing well with triglycerides, A1c, and other risk markers.
- Can support conversations about inflammation-related symptoms by quantifying one modifiable input.
- Useful for monitoring changes after diet shifts (more fish, fewer seed oils) or omega-3 therapy adjustments.
- Highlights when a “normal-looking” diet may still produce a high omega-6 to omega-3 pattern for you.
- Works well as a trend marker so you can retest and confirm whether your plan is actually moving the needle.
What is the Arachidonic Acid/EPA Ratio?
The arachidonic acid/EPA ratio compares two polyunsaturated fatty acids in your blood: arachidonic acid (AA), an omega-6 fat, and eicosapentaenoic acid (EPA), an omega-3 fat. Your body uses AA and EPA as raw materials to make signaling molecules (eicosanoids and related mediators) that influence inflammation, blood vessel tone, and platelet activity.
A higher ratio generally means AA is high relative to EPA, which can reflect a pattern of higher omega-6 intake, lower omega-3 intake, or both. A lower ratio generally means EPA is relatively higher, which is often seen with regular fatty fish intake or omega-3 supplementation.
Different labs may measure fatty acids in different blood fractions (for example, red blood cell membranes versus plasma/whole blood). That matters because some fractions reflect shorter-term intake and others reflect longer-term patterns. When you retest, try to use the same lab method so your trend is meaningful.
Why ratios are used instead of a single fatty acid
AA and EPA can both move up or down depending on diet, metabolism, and lab method. A ratio helps summarize the balance between competing pathways, which is often what clinicians care about when they are thinking about inflammatory signaling.
How quickly the ratio can change
If your test is based on plasma or whole blood, changes can show up within weeks of consistent intake. If it is based on red blood cell membranes, it may reflect a longer window (often closer to a few months). Your report or ordering details may indicate the specimen fraction used.
What do my Arachidonic Acid/EPA Ratio results mean?
Low AA/EPA ratio
A low ratio usually means EPA is relatively high compared with arachidonic acid. This is commonly seen when you eat fatty fish regularly or take omega-3 supplements consistently. In many contexts, a lower ratio is considered a favorable balance, but very low values can be a cue to review dose, bleeding risk factors, and medications with your clinician rather than assuming “lower is always better.”
Optimal AA/EPA ratio
An “optimal” ratio is the range where your omega-6 and omega-3 balance supports your goals without suggesting extremes. The exact target can vary by lab method and clinical context, so your reference interval matters. If your ratio is in range and stable, the most useful next step is often to focus on other risk markers (lipids, glucose, blood pressure) and keep your dietary pattern consistent.
High AA/EPA ratio
A high ratio means AA is high relative to EPA, which often reflects low omega-3 intake, higher omega-6 intake, or limited conversion/absorption. It does not prove you have inflammation or cardiovascular disease, but it can be a practical signal that your fatty acid pattern may not match your health goals. Many people use this result to guide food choices (more omega-3 sources) and then retest after a consistent period to confirm improvement.
Factors that influence your AA/EPA ratio
Your ratio is influenced by diet (fatty fish, fish oil, and omega-6–rich oils), consistency over time, and the blood fraction the lab measures. Genetics, body weight changes, and metabolic health can affect how fats are incorporated into cell membranes. Certain medications and conditions that affect lipid metabolism can shift fatty acid patterns, and alcohol intake can indirectly influence related lipid markers. For clean comparisons, retest under similar conditions and avoid changing supplements in the week or two right before your draw unless your clinician advises otherwise.
What’s included
- Arachidonic Acid
- Arachidonic Acid/Epa Ratio
- Dha
- Dpa
- Epa
- Epa+Dpa+Dha
- Ferritin
- Folate, Serum
- Iron Binding Capacity
- Iron, Total
- Linoleic Acid
- Omega-3 Total
Similar tests to consider
Frequently Asked Questions
What is a good AA/EPA ratio?
“Good” depends on the lab method and the reference interval on your report, because different specimen fractions can produce different typical values. In general, a lower AA/EPA ratio suggests relatively higher EPA (often a more omega-3–forward pattern), while a higher ratio suggests relatively lower EPA. The most actionable approach is to pick a target with your clinician and then track your trend using the same test method.
Do I need to fast for an AA/EPA ratio test?
Many fatty acid measurements do not strictly require fasting, but some panels are ordered alongside lipids or triglycerides that may be affected by recent meals. Follow the instructions provided with your order, and try to repeat the same conditions when you retest so your results are comparable.
How long after starting fish oil should I retest?
A common retest window is 8–12 weeks, especially if the test reflects longer-term incorporation into red blood cell membranes. If your test reflects plasma or whole blood, changes may appear sooner, but consistency still matters. Retesting too early can miss the full effect of a stable dose.
Is AA/EPA the same as the omega-6 to omega-3 ratio?
Not exactly. AA/EPA compares two specific fatty acids, while an omega-6 to omega-3 ratio may sum multiple omega-6 and omega-3 fats. AA/EPA is often used because AA and EPA are directly involved in pathways that generate inflammatory and anti-inflammatory mediators.
Can a high AA/EPA ratio cause symptoms?
The ratio itself does not cause symptoms, and it cannot diagnose inflammation-related conditions. However, it can reflect a fatty acid pattern that may contribute to inflammatory signaling in some people. If you have symptoms, it is best used as one piece of a broader evaluation that includes history, exam, and other labs.
What should I look at with my AA/EPA ratio for a fuller picture?
Many people review it alongside triglycerides, HDL and LDL cholesterol, hemoglobin A1c (or fasting glucose/insulin), and markers of overall cardiometabolic health. If your panel includes DHA or an omega-3 index, those values help you see whether the ratio is changing because EPA rose, AA fell, or both.