N-Methylhistamine, 24 Hour Urine

Test Overview

Method

Various

Method Description

N-Methylhistamine: LC-MS/MS
Creatinine: Enzymatic Colorimetric Assay

Result Included

N-Methylhistamine; Creatinine Concentration; Creatinine

Aliases/Synonyms

1-Methylhistamine; Histamine Metabolites; Urinary N-Methylhistamine

Specimen

Specimen Type

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.

Containers

Collection Containers

24 Hour Urine Container

Volume

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: <a href="https://iclabs.ca/test/1959/">N-Methylhistamine, Random Urine</a>.

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	Refrigerated	Frozen
14 days	28 days	28 days

Performance & Interpretation

Turnaround Time

11 days

Results

N-methylhistamine

mcg/g creatinine

0-5 y: 120-510
6-16 y: 70-330
> 16 y:30-200
Creatinine

mg/24 hours

Males: 930-2955
Females: 603-1783

Comment

Reference values have not been established for patients who are younger than 18 years of age.

Referral Location

Out-of-Country

Interface & Setup

HL7 Interface Codes

Order Code	Result Name	Result Codes	Units
NMHIS U	N-Methylhistamine, 24Hr, U	62304	mcg/g Cr
	Creatinine Concentration, 24Hr, U	62305	mg/dL
	Creatinine, 24 HR , U	63856	mg/24 h

Test Version

Last Updated

2022-12-15