ABSTRACT
In the study 74% of urine specimens with pyuria grew signfificant colony counts. In specimens with "normal" numbers of white blood cells in the positive urine cultures were obtained in 20%. The latter observation has been occasionally reported in the medical literature as instances of bacteriuria without pyuria. Further analysis of cases with "normal" leucocyturia with the use of the Sternheimer-Malbin stain revealed that positive urine cultures were obtained in those with pale blue type of white blood cells. The importance of this observation in the diagnosis of asymptomatic urinary tract infection was stressedTwo important parameters of renal function in correlation with pyuria were also assessed in this study: glomerular filtration rate by B.U.N., serum creatinine and endogenous creatinine clearance and concentrating ability by Fishberg concentration test. The limitation of B.U.N. and serum creatinine in estimating G.F.R. was pointed out since the values of these end products of protein metabolism do not go up unless G.F.R. is reduced by over 50%. The presence of normal creatinine clearance and Fishberg concentration test in patients with pyuria and bacteriuria are strong evidences favoring the confinement of the urinary infection to the lower tract. Impaired creatinine clearance and concentration tests are observed in patients with pyelonepthritis and other underlying renal diseases with or without superimposed infection.(Summary and Conclusions)