--- title: TMAO Test type: biomarker url: "https://www.test-well.com/biomarkers/tmao" also_known_as: - tmao - trimethylamine n-oxide - tmao (trimethylamine n-oxide) - tmao (trimethylamine n oxide) category: Heart Health units: - umol/L - "µmol/L" - uM order_price_usd: 44.99 order_item: TMAO (Trimethylamine N-Oxide) order_url: "https://www.test-well.com/tests/tmao-trimethylamine-n-oxide" reviewed_at: 2026-10-09 --- # TMAO > TMAO is measured with a standard blood draw after an 8–12 hour fast. A typical reference range is 0.000 – 6.20 umol/L. At TestWell it's $44.99 all-in as TMAO (Trimethylamine N-Oxide), results in 3–5 business days, drawn at Quest. An out-of-range result is a prompt to look closer, not a diagnosis. Also known as: tmao, trimethylamine n-oxide, tmao (trimethylamine n-oxide), tmao (trimethylamine n oxide). ## Key facts | Fact | Value | | --- | --- | | Units | umol/L / µmol/L / uM | | Sample | Blood draw | | Fasting | 8–12 hours | | Results | 3–5 business days | | Price | $44.99 | | Labs | Quest | ## What does TMAO measure? A metabolite produced when gut bacteria break down choline and carnitine from the diet and the liver oxidizes the result. Higher TMAO has been associated with cardiovascular and kidney risk independent of cholesterol. ## What is the normal range for TMAO? | Population | Reference range | | --- | --- | | age 18+ | 0.000 – 6.20 umol/L | Reference intervals differ slightly between labs; the range printed on your report is the one to interpret against. Ranges are usually set so 95% of healthy people fall inside them. ## What does a high TMAO mean? Associated with higher cardiovascular risk; responds within weeks to reducing red meat and egg-yolk intake. Reduced kidney function also raises it. ## How do you get tested for TMAO? | Order | Type | Price | Includes | | --- | --- | --- | --- | | [TMAO (Trimethylamine N-Oxide)](https://www.test-well.com/tests/tmao-trimethylamine-n-oxide) | Single test | $44.99 | This marker | | [Men's Total Body Advanced Panel](https://www.test-well.com/tests/mens-total-body-advanced-panel) | Panel | $999.99 | 65 tests | | [Women's Total Body Advanced Panel](https://www.test-well.com/tests/womens-total-body-advanced-panel) | Panel | $999.99 | 65 tests | ## Quest vs Labcorp vs BioReference | Lab | Available | Price | Notes | | --- | --- | --- | --- | | Quest Diagnostics | Yes | $44.99 | Choose Quest at checkout; walk-in patient service centers in every state TestWell serves outside NY and NJ. | | Labcorp | No | — | Not offered through Labcorp for this test. | | BioReference (NY & NJ) | No | — | Not available in NY/NJ for this test. | ## Common questions about TMAO ### Do I need a doctor's order to test my tmao? No. TestWell's licensed physician network reviews and approves your order — usually within minutes. You can place an order online without an in-person visit or a referral from your own doctor. ### How long does it take to get TMAO results? Most TMAO results are available in 1–3 business days after your specimen arrives at the lab. You'll get an email the moment your results are ready, with everything viewable in your TestWell portal. ### How much does a TMAO test cost? Our TMAO (Trimethylamine N-Oxide) starts at $44.99. That's the all-in price — no copays, no insurance hoops, no surprise bills. HSA and FSA cards are accepted. ### Do I need to fast before my TMAO test? Yes — for the most accurate result, fast for 8–12 hours before your blood draw. Water is fine; coffee, food, and supplements are not. Your prep instructions will be included with your order. ### Which lab will process my TMAO test? Your test will be processed by Quest Diagnostics, Labcorp, or BioReference depending on which is closest to you and which lab carries the test. All three are CLIA-certified and trusted by hospitals nationwide. You'll choose your lab during checkout from 4,000+ locations. ## Sources - [Cleveland HeartLab — TMAO](https://www.clevelandheartlab.com/tests/tmao-trimethylamine-n-oxide/) ## Related biomarkers - [Apolipoprotein B](https://www.test-well.com/biomarkers/apolipoprotein-b) - [Lipoprotein(a)](https://www.test-well.com/biomarkers/lipoprotein-a) - [NT-proBNP](https://www.test-well.com/biomarkers/nt-probnp) - [Homocysteine](https://www.test-well.com/biomarkers/homocysteine) - [LDL Particle Number](https://www.test-well.com/biomarkers/ldl-particle-number) - [Small LDL Particle](https://www.test-well.com/biomarkers/small-ldl-particle) - [Reference range lookup tool](https://www.test-well.com/tools/reference-range-lookup) - [Lab unit converter](https://www.test-well.com/tools/lab-unit-converter) - [All biomarkers](https://www.test-well.com/biomarkers) --- Medically reviewed by Youmna DiStefano, MD (Medical Reviewer, TestWell); last reviewed 2026-10-09. Review policy: https://www.test-well.com/reviewers/youmna-distefano-md Canonical page: https://www.test-well.com/biomarkers/tmao Machine-readable catalog: https://www.test-well.com/api/catalog.json · MCP server: https://www.test-well.com/mcp · Overview for agents: https://www.test-well.com/llms.txt Prices are cash-pay, in USD, and include physician authorization; every order adds one flat $6 lab processing fee. Educational content is not a diagnosis — discuss results with a clinician.