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N-Methylhistamine, 24-Hour Urine
Ordering Recommendation
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 300 mL or greater is required. If submitting a random urine or 24-hour collection with a total volume of less than 300 mL, refer to N-Methylhistamine, Random Urine (3002743).
New York DOH Approval Status
Specimen Required
Patient must not be taking monoamine oxidase inhibitors (MAOIs) or aminoguanidine as these medications increase N-methylhistamine (NMH) levels.
24-hour urine.
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 300 mL.
Ambient: 2 weeks; Refrigerated: 28 days; Frozen: 28 days
Methodology
Quantitative Liquid Chromatography-Tandem Mass Spectrometry/Colorimetry
Performed
Varies
Reported
3-10 days
Reference Interval
By Report
Interpretive Data
Performed by non-ARUP Laboratory
Note
Hotline History
CPT Codes
82542
Components
| Component Test Code* | Component Chart Name | LOINC |
|---|---|---|
| 2011035 | Collection Duration | 13362-9 |
| 2011036 | Urine Volume | 3167-4 |
| 2011037 | N-Methylhistamine, 24 Hr Urine | 44340-8 |
| 2011038 | Creatinine Concentration, 24 Hr Urine | 20624-3 |
| 3002790 | Creatinine, 24 Hr Urine | 2162-6 |
Aliases
- 1-Methylhistamine
- Histamine Metabolites
- Urinary N-Methylhistamine
Mayo Clinic Laboratories
