Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Oct 12;59(3):619-624.
doi: 10.1515/cclm-2020-1263. Print 2021 Feb 23.

Comparison of the reliability of Gram-negative and Gram-positive flags of the Sysmex UF-5000 with manual Gram stain and urine culture results

Dietmar Enko  1   2 , Ingeborg Stelzer  2 , Michael Böckl  2 , Wolfgang J Schnedl  3 , Andreas Meinitzer  1 , Markus Herrmann  1 , Martin Tötsch  4 , Michael Gehrer  4
Affiliations

Comparison of the reliability of Gram-negative and Gram-positive flags of the Sysmex UF-5000 with manual Gram stain and urine culture results

Dietmar Enko et al. Clin Chem Lab Med. .

Abstract

Objectives: Recently, the fully automated flow cytometry-based UF-5000 (Sysmex Corboration, Kobe, Japan) urine sediment analyzer was developed providing bacteria (BACT) info flags for more accurate bacterial discrimination of urinary tract infections (UTIs). This study aimed to compare the reliability of the UF-5000 BACT-info flags with manual Gram stain and urine culture as the gold standard method.

Methods: A total of 344 urine samples were analyzed on the UF-5000 and compared with manual microscopic Gram stain and urine cultures. Agreement was assessed by Cohen's kappa (κ) analysis. The Youden index was used to determine the optimal BACT and white blood cell (WBC) cut-off points for discriminating positive and negative urine cultures.

Results: Overall 98/344 (28.5%) samples were urine culture positive at a cut-off of ≥105 CFU/mL. "Gram-negative?" UF-5000 BACT-Info flags showed a better concordance of 25/40 (62.5%) with urine culture compared to Gram stain with 30/50 (60%). The results for UF-5000 discrimination of Gram-positive and Gram-negative microorganisms demonstrated a substantial (κ = 0.78) and fair (κ = 0.40) agreement with urine culture. Optimal cut-off points detecting positive urine cultures were 135 BACT/µL (sensitivity [SE]: 92.1%, specificity [SP]: 85.4%, positive predictive value [PPV]: 71%, negative predictive value [NPV]: 96%) and 23 WBC/µL (SE: 73.5%, SP: 84.1%, PPV: 65%, NPV: 89%).

Conclusions: The UF-5000 analyzer (Sysmex) is a reliable diagnostic tool for UTI screening. The displayed BACT-Info flags allow a quick diagnostic orientation for the clinician. However, the authors suggest verifying the automated Gram categories with urine culture.

Keywords: automation; bacteriuria; urinalysis; urinary tract infections.

PubMed Disclaimer

References

    1. Magill, SS, Hellinger, W, Cohen, J, Kay, R, Bailey, C, Boland, B, et al. Prevalence of healthcare-associated infections in acute care hospitals in Jacksonville, Florida. Infect Control Hosp Epidemiol 2012;33:283–91. https://doi.org/10.1086/664048.
    1. Wilson, ML, Gaido, L. Laboratory diagnosis of urinary tract infections in adult patients. Clin Infect Dis 2004;38:1150–8. https://doi.org/10.1086/383029.
    1. European Confederation of Laboratory Medicine. European urinalysis guidelines. Scand J Clin Lab Invest Suppl 2000;231:1–86.
    1. Chu, CM, Lowder, JL. Diagnosis and treatment of urinary tract infections across age groups. Am J Obstet Gynecol 2018;219:40–51. https://doi.org/10.1016/j.ajog.2017.12.231.
    1. Le, Z, Li, F, Fei, C, Ye, A, Xie, X, Zhang, J. Performance of the Sysmex UF-1000i urine analyser in the rapid diagnosis of urinary tract infections in hospitalized patients. J Infect Chemother 2016;226:377–82. https://doi.org/10.1016/j.jiac.2016.02.009.

LinkOut - more resources