TMAO (Trimethylamine N-oxide)
Use
High levels of TMAO have been associated with an increased risk of heart disease.1
Special Instructions
TMAO is a dietary metabolite produced by a pathway involving gut microbiota. TMAO concentrations increase in the blood after ingestion of dietary choline and L-carnitine, which are abundant in meat, eggs, liver, and wheat germ and energy drinks. Choline and L-carnitine are metabolized in the gut by microbiota to form trimethylamine (TMA), which is subsequently oxidized in the liver into TMAO by flavin monooxygenases (FMOs). TMAO concentrations have been shown to be reduced in animals and humans treated with broad-spectrum oral antibiotics confirming the requirement for gut bacteria in the formation of TMA and TMAO.
Limitations
Interferences: Acetylsalicylic acid elicited 10% interference at 3.5 mg/dL, while its active metabolite, salicylic acid, elicited 10% interference at 42 mg/dL. Protein (albumin) elicited 10% interference at 0.83 mg/dL. Bilirubin (unconjugated) elicited 10% interference at 10.1 mg/dL. Uric acid elicited 10% interference at 13.8 mg/dL. This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Other
Biomarkers
LOINC Codes
- 93765-6
Result Turnaround Time
3-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
Spun NMR LipoTube (black-and-yellow-top tube) is the preferred container; lavender-top (EDTA) tubes or plain red-top (no gel) tubes also are acceptable specimens.
Collection Instructions
Keep NMR LipoTube upright at room temperature for 30 minutes and allow to clot. Centrifuge at 1600 to 1800 xg for 10 to 15 minutes immediately after clotting. If the sample cannot be centrifuged immediately, it must be refrigerated at (2°C to 8°C) and centrifuged within 24 hours of collection. The NMR tube should then be stored at (2°C to 8°C) until shipped. Do not open NMR LipoTube.
Patient Preparation
TMAO levels are lower in humans who follow a vegetarian or vegan diet than in omnivores. Patients should fast overnight and refrain from consuming fish and other marine food items the day before the blood draw. Fasting for 10 to 12 hours is recommended.
Storage Instructions
Refrigerate.
Causes for Rejection
Unspun LipoTube; serum specimen drawn in gel-barrier collection tube other than the NMR LipoTube; sample older than 14 days
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |