The current standard for diagnosis of Eosinophilic Esophagitis (EoE) is endoscopy with esophageal biopsy to determine the eosinophil count. A non-invasive biomarker of eosinophil activation would be helpful in management. A recent study investigated urinary 3-bromotyrosine (3-BT) measurements as a possible biomarker.
An assay called the Eosinophil Quantitated Urine Kinetic was developed. In the EoE patients, median urinary 3-BT level was 93 times higher than the nonatopic (nonallergic) group and 13 times higher than the atopic (allergic) group. Subjects with urine 3-BT level greater than 20pg/400mg of creatinine were 4.8 times more likely to have EoE compared to atopic controls. An atopic disease flare was not associated with any difference in urinary 3-BT.
Urinary 3-BT is an exciting assay that may assist allergists for the diagnosis of EoE.