N-Methylhistamine, Random, Urine

Test Code

39604

CPT Codes
82542, 82570

Preferred Specimen

5 mL random urine collected in a sterile, screw-cap container with no preservative

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

Minimum Volume

3 mL

Instructions

1. Collect a random urine specimen within a few hours of symptom onset.
2. No preservative.

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.

Transport Temperature

Refrigerated (cold packs)

Specimen Stability

Room temperature: 14 days
Refrigerated: 28 days
Frozen: 28 days

Methodology
NMHR1: Liquid Chromatography-Tandem Mass Spectrometry
CRETR: Enzymatic Colorimetric Assay

Setup Schedule

Set up: Tues, Thurs; Report available: 3 days

Reference Range

Age	(mcg/g Cr)
0-5 years:	120-510
6-16 years:	70-330
> 16 years:	30-200

Creatinine, Random, U	See Laboratory Report

Clinical Significance

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.

Performing Laboratory
Mayo Clinic Laboratories
200 First Street SW
Rochester, MN 55905

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.