Leukotriene E4, 24 Hour Urine (Sendout)

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General Information

Lab Name
Leukotriene E4, 24 Hour Urine (Sendout)
Lab Code
RULTE4
Epic Name
Leukotriene E4, 24 Hour Urine (Sendout)
External Test Id
TLTE4
Description

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)
  • Increased excretion of LTE4 is nonspecific and should not be used alone to make a clinical diagnosis of a MC activation disease.

Test Highlights: Quantitation of urinary metabolites of histamine, prostaglandin D2, and leukotriene E4 may provide significant clues for the diagnosis and management of symptomatic patients with both clonal and nonclonal mast cell activation syndromes. The presence of 1 or more elevated levels of these biomarkers in urine greatly narrows diagnostic possibilities for causes of symptoms, informs the practitioner what specific metabolic pathways are involved, and targets the treatment in a specific, personalized fashion.

    For an optimal evaluation, testing for urinary leukotriene E4 should be accompanied with laboratory investigations for the presence of serum Tryptase [TRYPT], 2,3 Dinor 11 Beta Prostaglandin F2 Alpha, 24h Urine (Sendout) [RU23BP], and N Methylhistamine, 24 Hour Urine (Sendout) [RUNMHT].

      Systemic mastocytosis is a heterogenous disease and lack of elevated LTE4 does not exclude the diagnosis of mast cell disease.

        Increased excretion of LTE4 has also been reported in the following conditions: asthma, eosinophilic pneumonia, respiratory syncytial virus infection, atopic dermatitis, Crohn disease, and rheumatoid arthritis.

          Ordering Requirements: Test pre-approved for orders originating from Fred Hutch, UW Medicine, or The Vancouver Clinic Allergy Clinics (MSALL, UESALL, VANTVC). Orders from other locations require Laboratory Medicine Resident (LMR) approval.

            Ordering Note: This test is for timed urine collections only. For random urine collections, refer to Leukotriene E4 (LTE4), Random Urine (Sendout) [RURLT4].

            Synonyms
            Cysteinyl Leukotriene, LTE4, Mast Cell Activation Syndrome, Mastocytosis, Systemic Mast Cell Activation, TLTE4
            Components
            Code Name
            RULTIN Leukotriene E4 Collection Interval
            RULTTV Leukotriene E4 Total Volume
            RULT4R Leukotriene E4, 24 Hour Urine
            RULTCR Creatinine, 24 Hour Urine
            RULTCC Creatinine Concentration, 24 Hour Urine

            Interpretation

            Method

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

            Creatinine: Enzymatic Colorimetric Assay

            Reference Range
            See individual components
            Ref. Range Notes

            Reference Range:

            Leukotriene E4: < or =104 pg/mg creatinine

            Interpretation: Elevated urinary leukotriene E4 (LTE4) concentrations above 104 pg/mg creatinine may be suggestive of mast cell activation syndrome if compatible features of disease are present.

            Ordering & Collection

            Specimen Type
            Urine
            Collection

            24 Hour Collection:

            • Start collection within a few hours of symptom onset.
            • Collect urine for 24 hours in a preservative-free amber polyethylene 24-hr urine collection container. Record the collection interval.
            • Refrigerate urine within 4 hours of completion of collection.
            Approval Required
            Test pre-approved for orders originating from Fred Hutch, UW Medicine, or The Vancouver Clinic Allergy Clinics (MSALL, UESALL, VANTVC). Orders from other locations require Laboratory Medicine Resident (LMR) approval.
            Handling Instructions

            Outside Laboratories:

            • Mix specimen well. Measure and record total volume. Document the total volume and collection interval on the DLMP requisition.
            • Aliquot 5 mL urine to a plastic screw-cap vial, leaving room for expansion. Freeze urine at -20°C while awaiting shipment. Transport samples on dry ice.
            Quantity
            Requested: 5 mL urine
            Minimum: 2 mL urine

            Processing

            Receiving Instructions
            • Mix specimen well. Measure and record total volume.
            • Document the collection interval and total volume on the requisition. Provide Sendouts with a copy.
            • Aliquot urine into a plastic screw-top vial, leaving room at the top for expansion. Freeze specimen at -20°C.

            Result-at-entry:

            • RULTIN (Leukotriene E4 Collection Interval): <Enter the interval in hr>
            • RULTTV (Leukotriene E4 Total Volume): <Enter the volume in mL>

            Sendouts:

            • Order Mayo Test: TLTE4.
            • Interfaced: Yes.
            Misc Sendout

            Performance

            Lab Department
            Sendouts Mayo Lab (FZ)(MAFZ)
            Frequency
            Performed: Monday, Thursday. Report Available: 2-9 days from sample receipt.
            Available STAT?
            No
            Performing Location(s)
            Sendout Mayo Clinic Laboratories
            800-533-1710

            200 First Street Southwest
            Rochester, MN 55901
            Sendout Mayo Clinic Laboratories (Superior Drive)
            800-533-1710

            3050 Superior Drive NW
            Rochester, MN 55901

            Billing & Coding

            CPT Codes
            82542
            LOINC
            30896-5
            Interfaced Order Code
            UOW5800