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Lab Test Dictionary

3-Methoxytryramine, 24 Hour, Urine (3MT)


Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)


3MT; 3-methoxy-4-hydroxyphenethylamine; Methoxytyramine; Methoxytramine; 3-Methoxytramine; 3-Methoxytyramine; Urine Dopamine

Specimen Type

Urine, Timed Collection

Performing Lab

Mayo Medical Lab

Epic ID

Other Reference Test

Lab Test Days

Monday-Friday; 4 P.M.

Standard TAT

3-5 Days

Collection Information

Specimen Required

2-10 mL 24-Hour Urine

Container Type

Sterile Container

Collection Instructions

Patient Preparation: Tricyclic antidepressants, labetalol, and sotalol medications may elevate levels of catecholamines producing results that cannot be interpreted. If clinically feasible, it is optimal to discontinue these medications at least 1 week before collection. Levodopa (Sinemet) medication will cause false-positive results. For advice on assessing the risk of removing patients from these medications and alternatives, you may consider consultation with a specialist in endocrinology or hypertension. Complete 24-hour urine collections are preferred, especially for patients with episodic hypertension; ideally the collection should begin at the onset of a "spell." Add 10 g (pediatric: 3 g) of boric acid as preservative within 4 hours of completion of the collection.

Processing Information - Lab Use Only

Transport Temperature


Specimen Stability

Room Temp: 28 Days; Refrigerated: 28 Days (Preferred); Frozen: 90 Days

Test Volume Required

10 mL 24-Hour Urine

Minimum Test Volume

2 mL 24-Hour Urine

Processing Instructions

Add 10 g (pediatric: 3 g) of boric acid or 50% Acetic Acid as preservative (preferred) within 4 hours of completion of the collection. 6M Hydrochloric Acid, 6M Nitric Acid, Sodium Carbonate or Toluene as preservatives are also acceptable. 24-Hour volume is required. Order in Mayolink and send with Mayo courier Monday-Friday.

CPT Codes