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
356-8593
Specimen(s):
Collection Medium:
Urine - 24 hour/timed plastic urine container
Minimum:
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.
Comments:
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.

Cautions:
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.
Methodology:
LTE4: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
AACT: Enzymatic Colorimetric Assay
CPT Code:
82542