Ordering Recommendation

Aids in the initial diagnosis of suspected mast cell activation disorders. A 24-hour urine collection of 300 mL or greater is required. If submitting a random urine or 24-hour collection with a total volume of less than 300 mL, refer to Leukotriene E4, Random Urine (3002351).

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Patients taking 5-lipoxygenase inhibitor zileuton (Zyflo) may have decreased concentrations of leukotriene E4 (LTE4). If possible, discontinue 48 hours prior to collection.


24-hour urine. Refrigerate during collection.

Specimen Preparation

From a well-mixed 24-hour collection transfer 5 mL urine to ARUP standard transport tubes (Min: 2 mL).
Test is not performed at ARUP; separate specimens must be submitted when multiple tests are ordered.

Storage/Transport Temperature

Frozen. Also acceptable: Refrigerated

Unacceptable Conditions

Collection duration and urine volume must be provided for testing. Total collection volume must be greater than 300 mL.


Ambient: 24 hours; Refrigerated: 1 week; Frozen: 28 days


Quantitative Colorimetry/Liquid Chromatography-Tandem Mass Spectrometry




3-12 days

Reference Interval

By Report

Interpretive Data

Compliance Category

Performed by non-ARUP Laboratory


Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
3004163 Creatinine, 24 Hour Urine 2162-6
3004164 Collection Duration: 13362-9
3004165 Urine Volume: 3167-4
3004166 Creatinine Concentration, 24 Hour Urine 20624-3
3004793 Leukotriene E4, 24 Hour Urine 101115-4
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Cysteinyl Leukotriene
  • LTE4
  • Mastocytosis
  • Systemic mast Cell Activation
Leukotriene E4, 24-Hour Urine

Mayo Clinic Laboratories