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Test Code NMHR N-Methylhistamine, Random, Urine


Advisory Information


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. See NMH24 / N-Methylhistamine, 24 Hour, Urine.



Specimen Required


Patient Preparation: Patient must not be taking monoamine oxidase inhibitors (MAOIs) or aminoguanidine as these medications increase N-methylhistamine (NMH) levels.

Supplies: Aliquot Tube, 5 mL (T465)

Container/Tube: Plastic vial, 5-mL

Specimen Volume: 5 mL

Collection Instructions:

1. Collect a random urine specimen within a few hours of symptom onset.

2. No preservative.


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 random urine 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
NMHR1 N-Methylhistamine, Random No Yes
CRETR Creatinine, Random, U No Yes

Method Name

NMHR1: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

CRETR: Enzymatic Colorimetric Assay

Reporting Name

N-Methylhistamine, Random, U

Specimen Type

Urine

Specimen 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

0-5 years: 120-510 mcg/g creatinine

6-16 years: 70-330 mcg/g creatinine

>16 years: 30-200 mcg/g creatinine

Day(s) and Time(s) Performed

Tuesday, Thursday; 10 a.m.

Performing 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 U.S. Food and Drug Administration.

CPT Code Information

82542

82570

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NMHR N-Methylhistamine, Random, U 13781-0

 

Result ID Test Result Name Result LOINC Value
605015 N-Methylhistamine, Random, U 13781-0
CRETR Creatinine, Random, U 2161-8