TMAO levels: what's normal, high and low
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.
Medically reviewed by Youmna DiStefano, MD · Last reviewed October 2026
The short answer
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.
- Units
- umol/L / µmol/L / uM
- Sample
- Blood draw
- Fasting
- 8–12 hours
- Results
- 3–5 business days
- Price
- $44.99
- Labs
- Quest
TMAO Reference Range
These are the typical adult reference ranges used by major US labs. Your report will include the specific range used by the lab that processed your sample.
| Population | Range |
|---|---|
| age 18+ | 0.000 – 6.20 umol/L |
Reference ranges are educational. Always interpret your result with the specific range printed on your lab report and discuss anything outside the range with a clinician.
Have a result in hand? analyze it with your AI assistant using these reviewed ranges, or run it through our explainer. Tools: look up another marker's range · convert lab units
What your TMAO result may mean
Associated with higher cardiovascular risk; responds within weeks to reducing red meat and egg-yolk intake. Reduced kidney function also raises it.
Educational only — not a diagnosis. Many factors can influence a single result. Discuss anything that concerns you with a healthcare provider.
How do you get a TMAO test?
Order online, a licensed physician reviews the requisition, and you walk into a nearby lab for the draw. TMAO is available on its own or inside these panels — panels cost less per marker when you want the fuller picture.
| Option | Includes | Price |
|---|---|---|
| TMAO (Trimethylamine N-Oxide) | This marker only | $44.99 |
| Men's Total Body Advanced Panel | 65 tests | $999.99 |
| Women's Total Body Advanced Panel | 65 tests | $999.99 |
Quest vs. Labcorp for TMAO: which lab should you pick?
Both are CLIA-certified national labs and the result is clinically equivalent, so pick whichever location is closer. Your report will print that lab's own reference range, which can differ slightly from the table above.
| Lab | Available | Price |
|---|---|---|
| Quest Diagnostics | Yes | $44.99 |
| Labcorp | No | — |
| BioReference (NY & NJ) | No | — |
Need help choosing a location? Use the lab finder to see draw sites near your ZIP.
Sources
Related Heart Health biomarkers
Markers commonly tested alongside TMAO.
Frequently asked
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. A single result above the reference range is a prompt to look closer with a clinician — often a repeat test and related markers — not a diagnosis on its own.
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.
Ready to test your tmao?
Order in two minutes, get physician-approved, and visit a lab the same day. Starts at $44.99.