Three TechniquesComparedfor DetectingBacteriunain Symptomatic Patients Koppel

We wanted to determinewhetherthe microscopicevaluation ofurinary sedimentcouldbe replacedbyeithera biochemical determination (Chemstnp-9) or a colonmetric staining procedure (Bac-T-Screen), and to evaluate the feasibilityof omittingfrom unnalysesattemptsto cultureurines.Cultureswere considered positive when colony counts were iO for catheterizedpatientsand i 0 for noncatheterizedpatients. The results of three separate studies on symptomaticpatients showed a progressivedecline in the sensitivityof the Chemstrip-9,which is a test for leukocyteesterase activity, and a difference in the sensitivity of the Bac-T-Screen between two of the studies. Neither test was consistently more sensitiveor more predictiveof a positiveculturethan was urine microscopy. By the end of the third study, we were convinced that the three methods are comparably sensitive and specific.Because 13 to 36% of positive cultures would be missed by these techniques, urine from symptomatic patientsshouldroutinelybe cultured.