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HelpTest ID NMH24 N-Methylhistamine, 24 Hour, Urine
Ordering Guidance
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 NMHR / N-Methylhistamine, Random, Urine.
Necessary Information
Specimen volume and duration are required.
Specimen Required
Patient Preparation: Patient must not be taking monoamine oxidase inhibitors (MAOIs) or aminoguanidine as these medications increase N-methylhistamine (NMH) levels.
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Container/Tube: Plastic, 5-mL tube
Specimen Volume: 5 mL
Collection Instructions:
1. Collect urine for 24 hours.
2. No preservative.
3. Aliquot into plastic tube and send at refrigerate temperature.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Useful For
Screening for and monitoring of mastocytosis and disorders of systemic mast-cell activation, such as anaphylaxis and other forms of severe systemic allergic reactions using 24-hour urine collection specimens
Monitoring therapeutic progress in conditions that are associated with secondary, localized, low-grade persistent, mast-cell proliferation and activation such as interstitial cystitis
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| NMH1D | N-Methylhistamine, 24 Hr, U | No | Yes |
| CRT24 | Creatinine, 24 HR, U | No | Yes |
Special Instructions
Method Name
NMH1D: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
CRT24: Enzymatic Colorimetric Assay
Reporting Name
N-Methylhistamine, 24 Hr, USpecimen Type
UrineSpecimen Minimum Volume
3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 28 days | |
| Frozen | 28 days | ||
| Ambient | 14 days |
Reference Values
N-METHYLHISTAMINE
0-5 years: 120-510 mcg/g creatinine
6-16 years: 70-330 mcg/g creatinine
>16 years: 30-200 mcg/g creatinine
CREATININE
Males: 930-2955 mg/24 hours
Females: 603-1783 mg/24 hours
Reference values have not been established for patients who are younger than 18 years of age.
For SI unit Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Day(s) Performed
Tuesday, Thursday
Report Available
3 to 7 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82542
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| NMH24 | N-Methylhistamine, 24 Hr, U | 44340-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CR_A | Creatinine, 24 HR, U | 2162-6 |
| 605159 | N-Methylhistamine, 24 Hr | 44340-8 |
| TM10 | Collection Duration | 13362-9 |
| VL8 | Urine Volume | 3167-4 |
| CR_24 | Creatinine Concentration, 24 HR, U | 20624-3 |