Aid in evaluation of patient with allergic signs and symptoms, such as anaphylaxis and other forms of severe systemic allergic reactions. May assist when diagnosing and monitoring mast-cell activation disorders or when evaluating histamine production over a longer time frame. Patients with chronic mast-cell activation often have chronically elevated N-methylhistamine (NMH) levels and will sometimes have intermittent NMH elevations. In these cases, N-Methylhistamine, 24-Hour Urine (2011034) is preferred.
Quantitative Liquid Chromatography/Tandem Mass Spectrometry/Colorimetry
Patient must not be taking monoamine oxidase inhibitors (MAOIs) or aminoguanidine as these medications increase N-methylhistamine (NMH) levels. Specimen should be collected within a few hours of symptom onset.
Transfer 5 mL urine to ARUP Standard Transport Tubes. (Min: 3 mL)
Test is not performed at ARUP; separate specimens must be submitted when multiple tests are ordered.
Refrigerated. Also acceptable: Room temperature and frozen.
Ambient: 2 weeks; Refrigerated: 28 days; Frozen: 28 days
Performed by non-ARUP Laboratory
|Component Test Code*||Component Chart Name||LOINC|
|3002744||N-Methylhistamine, Random Urine|
|3002745||Creatinine Concentration, Random Urine|
- Histamine Metabolites
- Urinary N-Methylhistamine
Mayo Clinic Laboratories