Uriglox® and Quantitative Urine Microscopy in Diagnosis of Urinary Tract Infection

Abstract

An alternative was sought to the sole use of abundant cultural findings as a basis for the diagnosis of urinary tract infection (UTI). Results obtained from the bacteriological culture of daytime urine specimens from 154 students by the dip slide method were checked against the findings from the quantitative culture, microscopy and Uriglox testing of the 1st morning urines voided later at home. As a diagnostic criterion, the finding of .gtoreq. 105 bacteria/ml urine in 2 successive cultures had an error of 19%. For the simultaneous occurrence in the morning urine of abundant bacteria (.gtoreq. 105/ml) and a subnormal glucose concentration (as revealed by the Uriglox test), this error was 1.5%. Only the latter combination showed the presence of UTI at the confidence level of .gtoreq. 95%, or was clinically significant. The specificity indices for the Uriglox test and the quantitative culture was 0.99 and 0.97, respectively. Microscopy of the morning urine showed .gtoreq. 103 bacteria/ml in all the subjects with infection but the number of leukocytes was normal in 1/5. The specificity indices for microscopic counts of .gtoreq. 103 organisms/ml and .gtoreq. 10 leukocytes/mm3 were 0.74 and 0.94, respectively. For higher counts, i.e. .gtoreq. 105 bacteria/ml and .gtoreq. 50 leukocytes/mm3, the specificity index of positive microscopy was 1.0. This specificity level was attained at the expense of the sensitivity, which for .gtoreq. 105 organisms/ml was 0.67 and for .gtoreq. 50 leukocytes/mm3 0.53. Abundant bacterial contamination of specimens often decisively complicates the diagnostic use of urine culture, and therefore the combined use of quantitative culture, microscopy and the Uriglox test is recommended as the principal tool for the diagnosis of UTI in ordinary hospital and ambulatory health services.