Urinary eosinophils.

The sensitivity of the presence of urinary eosinophils for the diagnosis of acute interstitial nephritis is 60%. Of those with interstitial nephritis without urinary eosinophils, in most cases, few eosinophils are present in the renal interstitial inflammatory infiltrate. The specificity of urinary eosinophils for acute interstitial nephritis has not been determined but urinary eosinophils have been reported with eosinophilic cystitis, urinary tract infections, and various renal diseases. However, the incidence of eosinophiluria in any of these conditions has not been investigated.