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HelpOrder Code MCMRU Mast Cell Mediators, 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. See MCM24 / Mast Cell Mediators, 24 Hour, Urine.
Specimen Required
Patient Preparation:
1. Patients taking monoamine oxidase inhibitors (MAOI) or aminoguanidine may have increased N-methylhistamine levels. If medically feasible, patient must not take MAOI or aminoguanidine for 3 weeks before specimen collection. For more information see Cautions.
2. Patients taking aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) may have decreased concentrations of prostaglandin F2 alpha. If medically feasible, the patient should not take aspirin for 2 weeks or NSAIDs for 72 hours before specimen collection.
3. Patients taking 5-lipoxygenase inhibitor zileuton (Zyflo) may have decreased concentrations of leukotriene E4. If medically feasible, the patient should not take zileuton for 48 hours before specimen collection.
Supplies: Urine Container, 60 mL (T313)
Collection Container/Tube: Plastic urine container
Submission Container/Tube: Plastic, 60-mL urine bottle
Specimen Volume: 20 mL
Collection Instructions:
1. Within a few hours of symptom onset, collect a random urine specimen.
2. No preservative.
Useful For
Evaluating patients at risk for mast cell activation syndrome (eg, systemic mastocytosis) using random urine collections
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| CRTFR | Creatinine, Random, U | No | Yes |
| RLTE1 | Leukotriene E4, Random, U | Yes, (order RLTE4) | Yes |
| R23B1 | 2,3-dinor 11B-Prostaglandin F2a | Yes, (order 23BPR) | Yes |
| RNMH1 | N-Methylhistamine, Random | Yes, (order NMHR) | Yes |
Method Name
CRT2F: Enzymatic Colorimetric Assay
RLTE1, R23B1, RNMH1: Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Mast Cell Mediators, Random, USpecimen Type
UrineSpecimen Minimum Volume
10 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Frozen | 28 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Reference Values
LEUKOTRIENE E4:
≤104 pg/mg creatinine
2,3-DINOR 11B-PROSTAGLANDIN F2a:
<1802 pg/mg creatinine
N-METHYLHISTAMINE:
0-5 years: 85-369 mcg/g creatinine
6-16 years: 48-238 mcg/g creatinine
>16 years: 19-143 mcg/g creatinine
CREATININE:
<18 years: Not established
≥18 years: 16-326 mg/dL
Method Description
N-methylhistamine:
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 (LC-MS/MS).(Unpublished Mayo method)
2,3-Dinor-11beta-prostaglandin F2alpha:
2,3-Dinor-11beta-prostaglandin F2alpha (23BPG) is quantified in urine by LC-MS/MS. Deuterium-labeled 23BPG internal standard is added to all controls and specimens, which are then liquid/liquid extracted. The eluent is evaporated, and samples/QC are then reconstituted prior to LC-MS/MS analysis.(Unpublished Mayo method)
Leukotriene E4:
Leukotriene E4 (LTE4) is quantified in urine via multiplexed LC-MS/MS. Deuterium-labeled LTE4 internal standard is added to all standards/controls/samples, which are then filtered. After additional sample clean-up, this eluent is analyzed by LC-MS/MS.(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 enable 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, Tuesday, Thursday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82570
84150
82542
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| MCMRU | Mast Cell Mediators, Random, U | 115845-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CRTFR | Creatinine, Random, U | 2161-8 |
| 620245 | N-Methylhistamine, Random, U | 13781-0 |
| 620241 | Leukotriene E4, Random, U | 33343-5 |
| 620243 | 2,3-dinor 11B-Prostaglandin F2a | 97658-9 |