Aids in the evaluation of patients with allergic signs and symptoms, such as anaphylaxis. May assist in diagnosing and monitoring mast cell activation disorders or in evaluating histamine production over a longer time frame. A 24-hour urine collection of ≥500 mL is required. If submitting a random urine or 24-hour collection with a total volume of <500 mL, refer to N-Methylhistamine, Random Urine (3002743).
Quantitative Liquid Chromatography/Tandem Mass Spectrometry/Colorimetry
New York DOH Approval Status
Patient must not be taking monoamine oxidase inhibitors (MAOIs) or aminoguanidine as these medications increase N-methylhistamine (NMH) levels.
From a well-mixed 24-hour collection transfer 5 mL urine to an ARUP Standard Transport Tube. (Min: 3 mL)
Test is not performed at ARUP; separate specimens must be submitted when multiple tests are ordered.
Refrigerated. Also acceptable: Room temperature or frozen.
Collection duration and urine volume must be provided for testing. Total collection volume must be greater than 500 mL.
Ambient: 2 weeks; Refrigerated: 28 days; Frozen: 28 days
Performed by non-ARUP Laboratory
|Component Test Code*||Component Chart Name||LOINC|
|2011037||N-Methylhistamine, 24 Hr Urine||44340-8|
|2011038||Creatinine Concentration, 24 Hr Urine||2161-8|
|3002790||Creatinine, 24 Hr Urine||2162-6|
- Histamine Metabolites
- Urinary N-Methylhistamine
Mayo Clinic Laboratories