Test Name: LEUKOTRIENE E4, RANDOM URINE
Test Code: 2193876
Alias:
Cysteinyl Leukotriene
LAB15168
RLTE4
Systemic Mast Cell Activation
CPT Code(s):
82542   82570  
Test Includes:

Leukotriene, Random Urine

Creatinine, Random Urine
Preferred Specimen:
5 mL Urine
Container:

Clear Urine Aliquot
Alternate Container:
Sterile Container
Minimum Volume:
2 mL Urine
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.
Transport Temperature:
Frozen
Stability:

Frozen (preferred): 28 days

Refrigerated: 7 days

Ambient: 24 hours
Rejection Criteria:
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Limitations:
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.
Additional Information:

Patient Preparation: Patients taking 5-lipoxygenase inhibitor zileuton (Zyflo) may have decreased concentrations of leukotriene E4 (LTE4). If medically feasible, the patient should not take zileuton for 48 hours before specimen collection.
Schedule:
Monday, Tuesday, Thursday; Report available: 2-9 days
Method:

Leukotriene E4: Liquid Chromatography - Tandem Mass Spectrometry (LC-MS/MS)

Creatinine: Enzymatic Colorimetric Assay 
Performing Lab:
Mayo Clinic Laboratory # RLTE4
Clinical Significance:

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
Use:
Updated: 02/23/2026
Reference Ranges:

Leukotriene E4: < or = 104 pg/mg creatinine

Creatinine: > or = 18 years old: 16-326 mg/dL

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

Health Lab Test Code Build Information

The CPT codes included in this publication are in accordance with Current Procedural Terminology, a publication of the American Medical Association. CPT codes are provided here for the convenience of our clients; however, correct coding often varies from one carrier to another, and HealthLab may bill specific carriers using codes other than those shown. Clients who bill for services should verify the code(s) with the applicable payor to confirm that their use is appropriate in each case.
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