Home
HelpOrder Code NMHR N-Methylhistamine, Random, Urine
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. order NMH24 / N-Methylhistamine, 24 Hour, Urine.
If ordering this test with 23BPR / 2,3-Dinor 11 Beta-Prostaglandin F2 Alpha, Random, Urine, both tests must be ordered under different order numbers. They cannot share an order number.
Specimen Required
Patient Preparation: Patient must not be taking monoamine oxidase inhibitors (MAOI) or aminoguanidine as these medications increase N-methylhistamine (NMH) levels.
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Container/Tube: Plastic vial
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, 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 |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.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
Method Description
N-methylhistamine (NMH) is removed from urine using solid phase extraction. The eluate is analyzed using liquid chromatography/tandem mass spectrometry and quantified using a stable isotope labeled internal standard, d3-NMH. NMH and d3-NMH are detected in multiple reaction monitoring mode using the specific transitions for m/z 126 to m/z 109, and m/z 129 to m/z 112, respectively.(Unpublished Mayo Method)
Creatinine:
The enzymatic method is based on the determination of sarcosine from creatinine with the aid of creatininase, creatinase, and sarcosine oxidase. The liberated hydrogen peroxide is measured via a modified Trinder reaction using a colorimetric indicator. Optimization of the buffer system and the colorimetric indicator enables the creatinine concentration to be quantified both precisely and specifically.(Package insert: Creatinine plus Ver 2. Roche Diagnostics; V15.0, 03/2019)
Day(s) Performed
Monday, Wednesday, Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82542
82570