--- title: TMAO (Trimethylamine N-Oxide) Test type: test id: tmao url: "https://www.test-well.com/tests/tmao-trimethylamine-n-oxide" price_usd: 44.99 lab_fee_usd: 6 all_in_usd: 50.99 category: Heart Health sample: Blood draw fasting_required: true results_in: "3–5 business days" labs: - Quest orderable: true order_url: "https://www.test-well.com/cart?add=tmao-trimethylamine-n-oxide&utm_source=ai_agent&utm_medium=markdown" --- # TMAO (Trimethylamine N-Oxide) Test > A gut-microbiome metabolite linked to cardiovascular risk — produced when gut bacteria break down choline and carnitine from red meat, eggs and dairy, measured from a standard blood draw. At TestWell it costs $44.99 plus a $6 lab processing fee, requires an 8–12 hour fast, and results post in 3–5 business days. Physician-authorized with no doctor's visit or insurance needed; draw at Quest. ## Key facts | Fact | Value | | --- | --- | | Price | $44.99 + $6 lab processing fee per order ($50.99 all-in for this test alone) | | Sample | Blood draw | | Fasting | Yes — 8–12 hours | | Results | 3–5 business days | | Labs | Quest Diagnostics | | Biomarkers measured | 1 | | Physician authorization | Included — no doctor's visit, referral or insurance needed | | Payment | Card, HSA or FSA; cash-pay only (no insurance billing) | ## What does the TMAO (Trimethylamine N-Oxide) test tell you? A gut-microbiome metabolite linked to cardiovascular risk — produced when gut bacteria break down choline and carnitine from red meat, eggs and dairy. Trimethylamine N-oxide is formed when gut bacteria metabolize dietary choline and L-carnitine into trimethylamine, which the liver then oxidizes to TMAO. Higher circulating TMAO has been associated with increased risk of heart attack, stroke and kidney disease in several large cohorts, independent of traditional risk factors, and it is one of the few blood markers that reflects the interaction between diet and the gut microbiome. Levels respond to dietary change within weeks, which makes TMAO useful for tracking the effect of reducing red meat or adjusting the diet. Kidney function affects clearance, so results are read alongside creatinine and cystatin C. ## Biomarkers measured - [TMAO](https://www.test-well.com/biomarkers/tmao) ## Price by lab | Lab | Test price | All-in (with $6 fee) | Notes | | --- | --- | --- | --- | | Quest Diagnostics | $44.99 | $50.99 | Choose at checkout; walk-in patient service centers nationwide (not NY/NJ) | Rhode Island is not served. Prices are identical online and in the lab; no draw fee or physician fee is added. ## How much does a TMAO (Trimethylamine N-Oxide) test cost? A TMAO (Trimethylamine N-Oxide) test costs $44.99 at TestWell — $50.99 all-in, since the $6 lab processing fee is charged once per order and there is no draw or physician fee. Hospital outpatient labs typically bill around $180.00 self-pay. With insurance you pay your plan's negotiated rate against your deductible; TestWell's price is fixed before the draw and HSA/FSA-eligible. | Where you order | Price | One test, all-in | Notes | | --- | --- | --- | --- | | TestWell (drawn at Quest) | $44.99 | $50.99 | Includes the one $6 lab processing fee, charged once per order | | Hospital outpatient lab, self-pay (typical) | $180.00 | $180.00 | Reference figure; hospital charges vary widely by facility and are often higher | Lab test codes: Quest test code 94154. ## How do you prepare? Fast for 8–12 hours (water only). Avoid fish and seafood for 24 hours before the draw — they can transiently raise TMAO. ## Common questions about the TMAO (Trimethylamine N-Oxide) test ### How long does it take to get TMAO (Trimethylamine N-Oxide) test results? TMAO (Trimethylamine N-Oxide) test results are typically ready in 3–5 business days after your draw at Quest. TestWell emails you the moment they post, and your results dashboard shows each marker against its reference range with a plain-English explanation. ### Do I need to fast, or can I eat before a TMAO (Trimethylamine N-Oxide) test? Yes. Fast for 8–12 hours (water only). Avoid fish and seafood for 24 hours before the draw — they can transiently raise TMAO. The [fasting before blood work guide](https://www.test-well.com/prep/fasting) covers how long to fast, what you can drink, and which results eating changes. ### Where can I get a TMAO (Trimethylamine N-Oxide) test near me without a doctor? Order the TMAO (Trimethylamine N-Oxide) test online from TestWell for $44.99 (plus a $6 per-order lab processing fee) — no doctor's visit, referral or insurance needed. A licensed physician authorizes the order, then you walk into any Quest patient service center near you for the draw (the lab locator on our site lists the closest ones by ZIP code), and results arrive in 3–5 business days. ### What is the Quest test code for a TMAO (Trimethylamine N-Oxide) test? The TMAO (Trimethylamine N-Oxide) test is Quest Diagnostics test code 94154. TestWell orders it under that code for $44.99 at Quest — no doctor's visit or insurance required, results in 3–5 business days. Codes verified against the labs' catalogs in 2026. ## How to order 1. Add to cart: https://www.test-well.com/cart?add=tmao-trimethylamine-n-oxide&utm_source=ai_agent&utm_medium=markdown 2. Create an account or sign in, confirm your state and preferred lab, pay by card, HSA or FSA. 3. A licensed physician authorizes the order (usually within minutes); the requisition arrives by email. 4. Walk into any Quest Diagnostics patient service center — no appointment needed at most sites. 5. 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Educational content is not a diagnosis — discuss results with a clinician.