Pyuria and Bacteriuria in Infants and Children: The Value of Pyuria as a Diagnostic Criterion of Urinary Tract Infections

PYURIA IS DEFINED by Dorland's Medical Dictionary 1 as "the presence of pus in the urine"; pus is defined as "a liquid inflammation product made up of cells (leukocytes) and a thin fluid called liquor puris." Wilson and Schloss 2 used the term "pyuria" to designate "the presence of sufficient pus to cause definite cloudiness of the urine." They further restricted the term to cases in which the pus cells were not only very numerous on microscopic examination, but also present in definite clumps. Smith 3 concluded that the diagnosis of pyuria is justified only when the number of leukocytes is "considerable, at least 8-10 per high-power field (HPF) in the uncentrifuged urine," but does not say whether in the catheterized or voided specimen; nor does he give data to support this conclusion. Several other authors 4-6 have reported varying normal and abnormal values for leukocytes in uncentrifuged and centrifuged