Synonym: TMAO.
Method(s): LC-MS/MS (1).

What is measured on the same platform, click here.
Platform C: Chol, (tChol), TMAO, Bet, DMG, tHcy, Creat, Crn, Met, MetSo, Cysta, tCys, His, 3-MH, 1-MH, Arg, ADMA, SDMA, hArg, TML

What is trimethylamine-N-oxide?

Choline, phosphatidylcholine and L-carnitine are cleaved by the gut microbiota to trimethylamine (TMA), which is oxidized to trimethylamine-N-oxide (TMAO) in the liver. TMAO seems to be proatherogenic in animal models and plasma levels are associated with risk of cardiovascular and other diseases in humans (2, 3).

Performance of the assay

Lower limit of detection (LOD): 0.02 µmol/L.
Within-day CV: 2.1-3.1 %; between-day CV: 3.0-3.1 %.


Assessment of choline status in relation to cardiovascular risk.

Specimen, collection and processing

Matrix: EDTA plasma is preferred if sarcosine is not measured simultaneously.
Volume: Minimum volume is 50 µL, but 200 µL is optimal and allows reanalysis.
Preparation and stability: The blood sample must be centrifuged and the plasma/serum fraction put on ice, and frozen.

Transportation; for general instruction on transportation, click here.

Frozen, on dry ice.

Reported values, interpretation

Reported values: 0.5-60.0 µmol/L
Intraclass correlation coefficient (ICC): 0.17-0.38.


1. Midttun, O., Kvalheim, G., and Ueland, P.M. (2013). High-throughput, low-volume, multianalyte quantification of plasma metabolites related to one-carbon metabolism using HPLC-MS/MS. Anal Bioanal Chem 405, 2009-017.
2. Cho, C.E., and Caudill, M.A. (2017). Trimethylamine-N-oxide: Friend, foe, or simply caught in the cross-fire? Trends Endocrinol Metab 28, 121-130.
3. Subramaniam, S., and Fletcher, C. (2018) Trimethylamine N-oxide: breathe new life. Br J Pharmacol 175, 1344-1353.