Evaluation of Sysmex UF-1000i and Alifax Alfred and HBL in rapid diagnosis of acute urinary tract infections in a hub and spoke setting

Abstract

This paper compares, in a hub and spoke (H&S) setting, the performance of two automated methods in rapid diagnosis of urinary tract infections (UTI). 2335 midstream urine samples obtained from adult patients were considered. In the spoke laboratory, rapid diagnosis of UTI was performed by using bacteria quantification with a Sysmex UF-1000i analyzer. In the hub laboratory, rapid diagnosis of UTI was performed by using Alifax Alfred and HB&L analyzer. Moreover, in the hub laboratory, a quantitative culture was performed in all samples. Using UF-1000i with a cut-off at 175 bacteria/µl, sensitivity was (SE) 0.95, specificity (SP) 0.80, negative predictive value (NPV) 0.98, positive predictive value (PPV) 0.64, and diagnostic accuracy (DA) 0.84. Using Alifax Alfred and HB&L with a cut-off at 30000 bacteria/ml, SE was 0.99, SP 0.99, NPV 0.99, PPV 0.98 and DA 0.98. In an H&S setting, UTI screening with UF-1000i is acceptable for routine applications. In our setting, after implementation of an UF-1000i based UTI screening, the number of bacterial cultures was thought to be reduced to 50%. Therefore, using the Alifax Alfred and HB&L system, with a higher SP, it was assumed that there is need to carry out further urine microbiological tests, allowing to perform reliable samples of about 70%. Another relevant positive aspect may be the availability of the negative results within 9 to 10 h after samples collection.