1-Methylhistamine; Histamine Metabolites; Urinary N-Methylhistamine
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N-Methylhistamine, 24 Hour Urine
Test ID: NMHIS U
Test
Aliases/Synonyms
Method
Various
Method Description
N-Methylhistamine: LC-MS/MS
Creatinine: Enzymatic Colorimetric Assay
Report Includes
N-Methylhistamine; Creatinine Concentration; Creatinine
Specimens
24h Urine
Patients with chronic mast cell activation often have chronically elevated N-methylhistamine (NMH) levels and will sometimes have intermittent NMH elevations. In these cases, a 24-hour urine collection is preferred.
Random urine collections are preferred for patients with episodic symptoms, for example in the context of allergic reactions, brought on by specific environmental factors; order N-Methylhistamine, Random Urine.
Patients with chronic mast cell activation often have chronically elevated N-methylhistamine (NMH) levels and will sometimes have intermittent NMH elevations. In these cases, a 24-hour urine collection is preferred.
Random urine collections are preferred for patients with episodic symptoms, for example in the context of allergic reactions, brought on by specific environmental factors; order N-Methylhistamine, Random Urine.
Test Location
Mayo Clinical Labs, Minnesota USA
Test Version
15-Dec-2022
Specimen
Specimens
24h Urine
Patients with chronic mast cell activation often have chronically elevated N-methylhistamine (NMH) levels and will sometimes have intermittent NMH elevations. In these cases, a 24-hour urine collection is preferred.
Random urine collections are preferred for patients with episodic symptoms, for example in the context of allergic reactions, brought on by specific environmental factors; order N-Methylhistamine, Random Urine.
Patients with chronic mast cell activation often have chronically elevated N-methylhistamine (NMH) levels and will sometimes have intermittent NMH elevations. In these cases, a 24-hour urine collection is preferred.
Random urine collections are preferred for patients with episodic symptoms, for example in the context of allergic reactions, brought on by specific environmental factors; order N-Methylhistamine, Random Urine.
Collection Containers
24 Hour Urine Container
Sample Volume
5 ml
Minimum Volume
3 ml
Specimen Comment
If the 24-hour collection volume (which must be provided with the order) is less than 300 mL, order the random urine test instead: N-Methylhistamine, Random Urine.
Patient Preparation
Patient must not be taking monoamine oxidase inhibitors (MAOIs) or aminoguanidine as these medications increase N-methylhistamine (NMH) levels.
Collection & Handling
Collection Instructions
Collect urine for 24 hours. Preservative not required.
Please note that when collecting for multiple tests, the following preservatives are acceptable for this test: 50% Acetic Acid, Boric Acid, 6M Hydrochloric Acid, 6M Nitric Acid, Sodium Carbonate.
Please note that Diazolidinyl Urea, Thymol and Toluene are not acceptable.
Handling Information
Aliquot into plastic tube. Store and send sample cold or frozen.
Additional Information
Provide collection volume and duration.
Stability
| Ambient | 14 days |
|---|---|
| Refrigerated | 28 days |
| Frozen | 28 days |
Test Version
15-Dec-2022
Performance / Interpretation
Method
Various
Method Description
N-Methylhistamine: LC-MS/MS
Creatinine: Enzymatic Colorimetric Assay
Turnaround Time
11 days
Results
| Name | Units | Reference Range | Conversion Factor | |
|---|---|---|---|---|
| N-methylhistamine | mcg/g creatinine |
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| Creatinine | mg/24 hours |
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Reference values have not been established for patients who are younger than 18 years of age.
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Test Location
Mayo Clinical Labs, Minnesota USA
Test Version
15-Dec-2022
Interface / Setup
HL7 Interface Codes
| Order Code | Result Codes | Units |
|---|---|---|
| NMHIS U | 62304N-Methylhistamine, 24Hr, U | mcg/g Cr |
| 62305Creatinine Concentration, 24Hr, U | mg/dL | |
| 63856Creatinine, 24 HR , U | mg/24 h |
Test Version
15-Dec-2022