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HelpTest Code RLTE4 Leukotriene E4, Random, Urine
Ordering Guidance
Patients with mast cell activation syndrome may have chronically elevated leukotriene E4 (LTE4), however, in certain situations LTE4 can exhibit intermittent elevations. In these cases, a 24-hour urine collection is preferred. For 24-hour urine collection, order TLTE4 / Leukotriene E4, 24 Hour, Urine.
Additional Testing Requirements
For an optimal evaluation, testing for urinary leukotriene E4 should be accompanied with laboratory investigations for the presence of serum tryptase (TRYPT / Tryptase, Serum), urinary 2,3-dinor 11 beta-prostaglandin F2 alpha (23BPR / 2,3-Dinor 11 Beta-Prostaglandin F2 Alpha, Random, Urine) and urinary N-methylhistamine (NMHR / N-Methylhistamine, Random, Urine).
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Container/Tube: Plastic vial
Specimen Volume: 5 mL
Collection Instructions:
1. Within a few hours of symptom onset, collect a random urine specimen.
2. No preservative
3. Aliquot urine into a plastic vial and send frozen.
Useful For
Aiding in the evaluation of patients at-risk for mast cell activation syndrome (eg, systemic mastocytosis, IgE-mediated allergies, or aspirin-exacerbated respiratory disease) using random urine collections
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| LTE4R | Leukotriene E4, Random, U | No | Yes |
| CRTFR | Creatinine, Random, U | No | Yes |
Method Name
LTE4R: Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
CRTFR: Enzymatic Colorimetric Assay
Reporting Name
Leukotriene E4, Random, USpecimen Type
UrineSpecimen Minimum Volume
2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Frozen (preferred) | 28 days | |
| Refrigerated | 7 days | ||
| Ambient | 24 hours |
Reference Values
LEUKOTRIENE E4
≤104 pg/mg creatinine
CREATININE
≥18 years old: 16-326 mg/dL
Reference values have not been established for patients who are younger than 18 years of age.
Interpretation
Elevated urinary leukotriene E4 concentrations above 104 pg/mg creatinine may be suggestive of mast cell activation syndrome if compatible features of disease are present.
Clinical Reference
1. Weiler CR. Mast cell activation syndrome: Tools for diagnosis and differential diagnosis. J Allergy Clin Immunol Pract. 2020;8(2):498-506
2. Gulen T, Akin C, Bonadonna P, et al. Selecting the right criteria and proper classification to diagnose mast cell activation syndromes: A critical review. J Allergy Clin Immunol Pract. 2021;9(11):3918-3928
3. Butterfield JH. Nontryptase urinary and hematologic biomarkers of mast cell expansion and mast cell activation: Status 2022. J Allergy Clin Immunol Pract. 2022;10(8):1974-1984
4. Valent P, Akin C, Metcalfe DD. Mastocytosis: 2016 updated WHO classification and novel emerging treatment concepts. Blood. 2017;129(11):1420-1427
5. Valent, P, Akin, C, Hartmann, K., et.al. Updated diagnostic criteria and classification of mast cell disorders: A consensus proposal. Hemasphere. 2021;5(11): e646
6. Divekar R, Hagan J, Rank M, et al. Diagnostic utility of urinary LTE4 in asthma, allergic rhinitis, chronic rhinosinusitis, nasal polyps, and aspirin sensitivity. J Allergy Clin Immunol Pract. 2016;4(4):665-670
7. Valent P, Hartmann K, Bonadonna P, et al. Global classification of mast cell activation disorders: An ICD-10-CM-adjusted proposal of the ECNM-AIM Consortium. J Allergy Clin Immunol Pract. 2022;10(8):1941-1950
8. Kolmert J, Gomez C, Balgoma D, et al. Urinary leukotriene E(4) and prostaglandin D(2) metabolites increase in adult and childhood severe asthma characterized by type 2 inflammation. A clinical observational study. Am J Respir Crit Care Med. 2021;203(1):37-53
9. Hagan JB, Laidlaw TM, Divekar R, et al: Urinary leukotriene E4 to determine aspirin intolerance in asthma: A systematic review and meta-analysis. J Allergy Clin Immunol Pract. 2017;5(4):990-997.e1. doi:10.1016/j.jaip.2016.11.004
10. Hayashi H, Fukutomi Y, Mitsui C, et al. Omalizumab for aspirin hypersensitivity and leukotriene overproduction in aspirin-exacerbated respiratory disease. A randomized controlled trial. Am J Respir Crit Care Med. 2020;201(12):1488-1498
11. Buchheit KM, Lewis E, Gakpo D, et al: Mepolizumab targets multiple immune cells in aspirin-exacerbated respiratory disease. J Allergy Clin Immunol. 2021;148(2):574-584
12. Buchheit KM, Sohail A, Hacker J, et al: Rapid and sustained effect of dupilumab on clinical and mechanistic outcomes in aspirin-exacerbated respiratory disease. J Allergy Clin Immunol. 2022;150(2):415-424
Day(s) Performed
Monday, Tuesday, Thursday
Report Available
2 to 9 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82542
82570
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| RLTE4 | Leukotriene E4, Random, U | 33343-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 603457 | Leukotriene E4, Random, U | 33343-5 |
| CRTFR | Creatinine, Random, U | 2161-8 |