Quantitative urinalysis. Diagnosing urinary tract infection in men

Abstract

Using a hemocytometer, the number of white blood cells(WBCs)/ml was determined in uncentrifuged urine specimens. Uninfected urine usually contained .ltoreq. 103 WBCs/ml, although up to 8 .times. 103 WBCs/ml were observed. Infected urine regularly contained > 104 WBCs/ml, and the mean WBC count/ml for urine from infected patients was 3.1 .times. 105. The absence of pyuria provides strong evidence against the presence of urinary tract infection. Similar results were obtained in patients who had indwelling catheters, suggesting that bacteriuria reflects the presence of infection rather than colonization. Valid data are easily obtainable by quantitative urinalysis of uncentrifuged urine specimens. There are obvious differences in WBCs per milliliter, with little overlap between infected and uninfected urine. This method of analysis should replace traditional means of counting WBCs per visual field in a centrifuged, resuspended urine sediment.