Urinary Markers

Urine samples are collected as a spot sample into a sterile plastic bag adherent to the skin at age 1 month and 1 year.

Eosinophil protein-X concentrations are determined by a double-antibody RIA immunoassay. Cysteinyl leukotriene and prostaglandin D2 concentrations are measured by Neogen ELISA test kits.

To standardize for variations in renal excretion, all urinary markers are adjusted for creatinine excretion. Urinary creatinine level is measured by buffered kinetic Jaffé reaction.