TMAO (Trimethylamine N-Oxide) Test
The TMAO test measures trimethylamine N-oxide in a blood sample. TMAO is a metabolite produced by gut bacteria and is described as related to processes involved in the development of atherosclerosis.
About this test
TMAO is a compound produced when gut bacteria act on nutrients such as phosphatidylcholine, choline and L-carnitine, found in foods including red meat, egg yolk and full-fat dairy. The liver converts the intermediate compound gut bacteria produce, TMA, into TMAO, which the test then measures directly from a serum sample.
TMAO has been described as regulating physiological processes involved in the development of atherosclerosis, a condition related to plaque buildup in arteries. Because it reflects both diet and gut bacteria activity, a clinician reads a TMAO result alongside a person's broader cardiovascular risk picture rather than as a standalone finding.
Test details
| Collection | Quest patient service center |
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Quest resources
Additional details
What this test looks at
The test reports one value: the concentration of TMAO in serum, measured using liquid chromatography/tandem mass spectrometry. Quest notes that fasting overnight and avoiding fish or other seafood the day before the blood draw helps avoid false elevations in the result, since seafood itself is a dietary source of compounds related to TMAO.
This test isn't part of the Celio Health store at the moment, so it can't be ordered or requested here. The test menu lists everything that can.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does the TMAO test measure?
It measures the concentration of trimethylamine N-oxide (TMAO) in a serum sample, using liquid chromatography/tandem mass spectrometry.
How is the TMAO sample collected?
The test uses a serum sample from a routine blood draw.
Do I need to prepare for a TMAO test?
Quest lists preparation for this test, including fasting overnight and avoiding fish or other seafood the day before the blood draw; preparation details appear with the test details.
What produces TMAO in the body?
Gut bacteria act on nutrients such as choline, phosphatidylcholine and L-carnitine, found in foods like red meat, egg yolk and full-fat dairy, and the liver converts the resulting compound into TMAO.
Does a TMAO result diagnose heart disease?
No. It is described as related to processes involved in atherosclerosis, and a clinician reads it together with other cardiovascular risk information rather than as a diagnosis on its own.