Clinical correlates of eosinophiluria.

We assessed the clinical correlates of eosinophils in the urine in 65 patients. In 16% of 470 patients whose urine was specifically examined, eosinophils were noted in the urine sediment. Review of the 65 patients with eosinophiluria demonstrated that when eosinophils were expressed as a percentage of total urine white blood cells, 85% (55/65 patients) had less than 5% urine eosinophils and 45% (29/65 patients) had less than 1%. Infection of the upper and lower urinary tract accounted for 45% of the clinical conditions associated with eosinophiluria. In nine (14%) of the 65 patients a diagnosis of acute interstitial nephritis could be made by clinical criteria or from renal biopsy specimens. We conclude that the finding of urine eosinophils is associated with a variety of clinical conditions and may be most useful when expressed as a percentage of total white blood cells in the urine. At a low-percentage positive (less than 5%), it may not be a good predictor of acute interstitial nephritis, but at a higher level (greater than 5%) it may be a more valuable predictor.