Pyuria and bacteriuria.

Urinary tract infection in childhood has long been recognized as a far from benign condition, yet the criteria for diagnosing such a condition are by no means uniform. While the final diagnosis rests on bacteriological evidence, the interpretation of significant bacteriuria in paediatric practice is particularly difficult. Various screening tests have been designed of which urine microscopy in search of pus cells remains the simplest. The accepted standard of significant pyuria varies from five or more pus cells per high power field in centrifuged urine (Kass, 1956), to ten or more pus cells per c.mm. in uncentrifuged urine (Dukes, 1928a, b; Stansfeld and Webb, 1953; Masters, 1953; Houston, 1963). Much controversy also arises about the correlation between pyuria and bacteriuria. While Stansfeld (1962) and Houston (1963) found close correlation between the two, Pryles and Eliot (1965) found only 61% of those with significant bacteriuria had 10 or more white cells/c.mm. of uncentrifuged urine. Doubts have been cast on the reliability of pyuria as a screening test for urinary tract infection (Kass, 1956; Randolph and Greenfield, 1964; Pryles and Eliot, 1965). It was the purpose of this study to reinvestigate the limit of urine white cell counts found in infants and children, their correlation with colony counts, and their reliability as a screening test for urinary tract infection.