Performance of the Sysmex UF1000i system in screening for significant bacteriuria before quantitative culture of...

To evaluate the performance of the Sysmex UF1000i automatic urine screening system in the quantitative culture of fast-growth aerobic/facultative bacteria.

A standard procedure was used to recover fast-growth aerobic/facultative micro-organisms in 1225 samples, applying (Sysmex(®)) flow cytometry for parallel bacteria and leucocyte counts. According to the area under the receiver operating characteristic curve, the optimal cut-off values to detect bacteriuria >10(5) colony forming units (CFU) ml(-1) were 690/μl for bacteria and 38/μl for leucocytes (sensitivity, 92%; specificity, 65%; positive predictive value [PPV], 39%; and negative predictive value [NPV], 97%). The use of a single cut-off point of 150 bacteria μl(-1) to detect significant bacteriuria of >10(5) CFU ml(-1) or of ≥10(4) CFU ml(-1) plus leucocyturia obtained similar results (sensitivity, 89%; specificity, 54%; PPV, 31%; and NPV, 96%) and allowed 45.7% of the samples to be rapidly excluded.

The Sysmex UF1000i system can be adapted for bacteriuria screening by the use of an appropriate cut-off point.

This screening system significantly reduces the workload and produces very few false positives and negatives.