The detection and interpretation of urinary eosinophils.

We determined the clinical diagnosis for 183 patients who had urine samples examined for the presence of eosinophils. Urine samples were examined with both Hansel's stain and Wright's stain. A total of 11% of these patients had eosinophils detected in the urine. A variety of clinical conditions were associated with eosinophiluria. Urinary tract infection and acute interstitial nephritis were most common, each accounting for 25% of the total patients with eosinophiluria. Eosinophiluria proved to be a good predictor of acute interstitial nephritis. Hansel's stain was superior to Wright's stain in detecting eosinophils in urine. In particular, Hansel's stain increased the sensitivity of eosinophiluria for acute interstitial nephritis (63% vs 25%) as well as its positive predictive value (50% vs 25%).