Bacteriuria screening with the new automated platform AutionMax-AutionEye: when to culture

Urinary tract infections (UTIs) are very common in clinical practice. Urine culture remains the cornerstone of UTI diagnosis, but urinalysis screening for bacteriuria can improve workflow. The aim of the study was to screen for significant bacteriuria using Aution Eye AI-4510, a flow cell digital urine sediment image analyzer recently introduced in Italy.

1,096 consecutive urine samples were studied. Samples were classified into three population groups: total population (n=1,096), 0-16 years (n=79), and >65 years (n=450). Each group was subdivided into females and males. At the established cut-offs, leukocyte (WBC) count, bacterial (BACT) count, or their combination with an and/or criterion, were then used to determine positivity. Results were compared to urine culture results obtained from the same samples.

Best screening was found in all groups, except the pediatric one, when WBC and BACT counts were combined. The total population group performed the best: at the defined cut-offs (WBC≥177; BACT≥1,000.5), sensitivity (SE) was 90.2 %, negative predictive value (NPV) was 96.9 %. The pediatric group showed inferior screening performance: the NPV was 78.8 % and the SE was 36.4 %. In the two subgroups of >65 years, males exhibited a strong screening reliability (DOR=36.2), while females showed a poor one (DOR=11.2).

Our findings show that the Aution Eye AI-4510 is an effective tool for screening urine samples. It quickly excludes patients who test negative for significant bacteriuria from further culturing, reducing unneeded urine cultures, and lowering expenses and workload. Furthermore, clinical decisions can be anticipated when screening is negative.