Test Directory

• Leukotriene E4
• Creatinine, 24 HR
• Creatinine Concentration, 24 HR

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 24-hour urine collections.

Specimen Type: 24 Hour Urine

Collection Container: 24 Hour Plastic Urine Container

Desired Specimen Volume: 5 mL

1. Start collection within a few hours of symptom onset.
2. Collect 24-hour urine in a timed urine collection jug.

1. Transfer 5 mL of urine into clear aliquot tubes (screw caps) and freeze.
2. Specimen must be frozen within 4 hours after completion of the 24-hour collection.
3. Specimen volume (in milliliters) and duration are required.
4. For an optimal evaluation, testing for urinary leukotriene E4 should be accompanied by laboratory investigations for the presence of serum tryptase, urinary 2,3-dinor 11 beta-prostaglandin F2 alpha and urinary N-methylhistamine.

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.

Transport to the laboratory frozen. 

See patient report.

Random urine collections are preferred for patients with episodic symptoms, (eg, in the context of allergic reactions brought on by specific environmental factors or mast cell activation syndrome).

• Cysteinyl Leukotriene
• LTE4
• Mast Cell Activation Syndrome
• Mastocytosis
• Systemic Mast Cell Activation
• Secondary MCAS
• Aspirin-exacerbated respiratory disease (AERD)
• Asthma
• IgE-dependent and independent asthma
• Idiopathic MCAS