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Lab Test Dictionary

Trimethylamine (TMA) and TMA N-oxide (TMAO), Quantitative, Urine (L6949)

Specimen Type


Performing Lab

Children's Hospital Colorado Biochemical Genetics

Epic ID

Other Reference Test

Collection Information

Specimen Required

1-5 mL Urine (Pre- and/or Post-Choline)

Container Type

Sterile Container

Collection Instructions

It is recommended to collect two urine specimens (Pre- and Post-Choline load) ordered separately, but one Post-Choline load is sufficient. For a Pre-Choline load specimen, 1-5 mL morning void urine, collected when the patient is eating an unrestricted diet and odor is present. For a Post-Choline load specimen, 1-5 mL morning void urine, should be collected about 12 hours after the patient has ingested choline bitartrate with a glass of orange juice or water (5 gm or 50000 mg). Freeze immediately after collection.

Processing Information - Lab Use Only

Transport Temperature


Test Volume Required

5 mL Urine (Pre- and/or Post-Choline)

Minimum Test Volume

1 mL Urine (Pre- and/or Post-Choline)

Processing Instructions

If possible, acidify the specimen to pH=4.0 before freezing. Complete a Children's Hospital Colorado Biochemical Genetics requisition and submit with specimen frozen Monday-Thursday only, no weekends of holidays. Clearly label specimens and requisitions Pre- and/or Post-Choline.

CPT Codes