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Test Code NMHR1 N-Methylhistamine, Random, Urine (Non-Orderable)


Ordering Guidance


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


Only orderable as part of a profile. For more information see NMHR / N-Methylhistamine, Random, Urine.

 

Patient Preparation: Patients taking monoamine oxidase inhibitors (MAOIs) may have increased levels of N-methylhistamine. If medically feasible, for 2 weeks before specimen collection, patient should not take MAOIs.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Container/Tube: Plastic, 5-mL tube

Specimen Volume: 5 mL

Collection Instructions:

1. Within a few hours of symptom onset, collect a random urine specimen.

2. No preservative.


Useful For

Only orderable as part of a profile. For more information see NMHR / N-Methylhistamine, Random, Urine.

 

Screening for and monitoring of mastocytosis and disorders of systemic mast-cell activation, such as anaphylaxis and other forms of severe systemic allergic reactions as a part of a random urine collection profile

 

Monitoring therapeutic progress in conditions that are associated with secondary, localized, low-grade persistent, mast-cell proliferation and activation such as interstitial cystitis

Reporting Name

N-Methylhistamine, Random

Specimen Type

Urine

Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  14 days

Reference Values

Only orderable as part of a profile. For more information see NMHR / N-Methylhistamine, Random, Urine.

 

0-5 years: 85-369 mcg/g creatinine

6-16 years: 48-238 mcg/g creatinine

>16 years: 19-143 mcg/g creatinine

Method Description

Isotopically labeled N-methylhistamine (NMH) is added to the sample as an internal standard (IS). NMH and IS are then purified from urine using solid phase extraction. The eluate is analyzed using liquid chromatography-tandem mass spectrometry.(Unpublished Mayo method)

Day(s) Performed

Monday, Wednesday, Friday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

82542

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NMHR1 N-Methylhistamine, Random 13781-0

 

Result ID Test Result Name Result LOINC Value
605015 N-Methylhistamine, Random, U 13781-0

Report Available

3 to 7 days

Specimen Minimum Volume

3 mL

Specimen Retention Time

14 days