Leukotriene E4
Label Mnemonic: LTE4
Epic Lab Code: LAB8635
Downtime Form: A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery
Commercial Mail-out Laboratory
5231 RCP
Specimen Instructions:
Refrigerate during 24 hour collection in plastic container. Maintain refrigeration when transporting urine (24 hour or random) to the laboratory.
Collection Medium:
Urine - 24 hour/timed plastic urine container
24 hour urine collection or random collection
Preferred Minimum: 4 mL urine
Absolute Minimum: 1 mL urine
Turn Around Time:
2 days upon receipt at reference laboratory
Reference Range:
< or =104 pg/mg creatinine
Interpretive Data:
Elevated urinary leukotriene E4 (LTE4) concentrations >104 pg/mg creatinine are consistent with the diagnosis of systemic mast cell disease when combined with clinical signs and symptoms. Pharmacological treatment with 5-lipoxygenase inhibitors or leukotriene receptor antagonists has been shown to decrease production of LTE4.

Urinary LTE4 may be used together with serum tryptase, urinary 2,3-dinor 11 beta-prostaglandin F2 alpha, and/or urinary N-methyl histamine.
Useful as an aid to evaluate patients suspected of having systemic mastocytosis.

When leukotriene E4 testing is performed, urine creatinine will always be performed at no additional charge.

Patients taking 5-lipoxygenase inhibitor Zileuton/Zyflo may have decreased concentrations of leukotriene E4 (LTE4) if dosage has not been discontinued for 48 hours.

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.

This assay measures both LTE4 and the 11-trans-LTE4 as markers of mast cell release.
LTE4: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
AACT: Enzymatic Colorimetric Assay
CPT Code: