Eosinophiluria.

Hansel's stain is a simple technique that can easily be performed in a clinical or office setting. It allows for improved detection of the eosinophiluria when compared with conventional Wright's stain. The mechanism underlying the superiority of the Hansel's stain remains to be elucidated. Eosinophiluria demonstrated by Hansel's stain appears to be a sensitive marker for drug-induced acute interstitial nephritis and probably allows differentiation from acute tubular necrosis. However, the spectrum of eosinophiluria also includes acute glomerulonephritis, rapidly progressive glomerulonephritis, prostatitis, and urinary tract obstruction. Therefore, the finding of eosinophiluria on Hansel's stain clearly cannot be considered diagnostic of acute interstitial nephritis. In the absence of renal biopsy or other clinical clues to suggest the diagnosis, eosinophiluria should not be used as the sole criterion for the diagnosis of acute interstitial nephritis or a a justification for empiric steroid therapy.