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
,
Ingeborg Stelzer
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.
Research funding: None declared.
Author contributions: DE wrote the manuscript and supervised this study project. All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
Competing interests: Authors state no conflict of interest.
Informed consent: Informed consent was not required because the urine samples were submitted for routine analysis only and patient data were anonymous.
Ethical approval: The ethical approval of this study was provided by the Ethical Committee of the Medical University Graz (Graz, Austria) and carried out with the current version of the Declaration of Helsinki.
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© 2020 Walter de Gruyter GmbH, Berlin/Boston
Artikel in diesem Heft
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Artikel in diesem Heft
- Frontmatter
- Editorial
- Complex analytical procedures in diagnostic laboratories and the IVDR
- Review
- Re-examining ferritin-bound iron: current and developing clinical tools
- Opinion Papers
- Designing a diagnostic Total Testing Process as a base for supporting diagnostic stewardship
- The end of the laboratory developed test as we know it? Recommendations from a national multidisciplinary taskforce of laboratory specialists on the interpretation of the IVDR and its complications
- EFLM Papers
- The Academy of the European Federation of Clinical Chemistry and Laboratory Medicine and the European Register of Specialists in Laboratory Medicine: guide to the Academy and the Register, version 4 – 2020
- A proposed Common Training Framework for Specialists in Laboratory Medicine under EU Directive 2013/55/EC (The Recognition of Professional Qualifications)
- Guidelines and Recommendations
- High-sensitivity cardiac troponin I and T methods for the early detection of myocardial injury in patients on chemotherapy
- General Clinical Chemistry and Laboratory Medicine
- Measurement of serum 17-hydroxyprogesterone using isotope dilution liquid chromatography-tandem mass spectrometry candidate reference method and evaluation of the performance for three routine methods
- Evaluation of carbohydrate-deficient transferrin measurements on the V8 capillary electrophoresis system and comparison with the IFCC approved HPLC reference method and N-Latex immunonephelometric assay
- The clinical relevance of anti-dsDNA antibodies determined by the Elia™ dsDNA assay in patients with negative indirect immunofluorescence on the HEp-2 cell
- A hierarchical bivariate meta-analysis of diagnostic test accuracy to provide direct comparisons of immunoassays vs. indirect immunofluorescence for initial screening of connective tissue diseases
- Individual uromodulin serum concentration is independent of glomerular filtration rate in healthy kidney donors
- Comparison of iohexol plasma clearance formulas vs. inulin urinary clearance for measuring glomerular filtration rate
- Overweight-obesity is associated with decreased vitamin K2 levels in hemodialysis patients
- Cardiovascular Diseases
- Evaluating the performance of an updated high-sensitivity troponin T assay with increased tolerance to biotin
- Infectious Diseases
- The anti-inflammatory cytokine response characterized by elevated interleukin-10 is a stronger predictor of severe disease and poor outcomes than the pro-inflammatory cytokine response in coronavirus disease 2019 (COVID-19)
- Quantification of the HIV-1 total reservoir in the peripheral blood of naïve and treated patients by a standardised method derived from a commercial HIV-1 RNA quantification assay
- Comparison of the reliability of Gram-negative and Gram-positive flags of the Sysmex UF-5000 with manual Gram stain and urine culture results
- Evaluation of a turbidimetric C-reactive protein assay to monitor early-onset neonatal sepsis in South Kivu (Democratic Republic of the Congo)
- Corrigendum
- Corrigendum to: Procalcitonin (PCT)-guided antibiotic stewardship in Asia-Pacific countries: adaptation based on an expert consensus meeting
- Letters to the Editor
- Decision-making based on sFlt-1/PlGF ratios: are immunoassay results interchangeable for diagnosis or prognosis of preeclampsia?
- Inter-center agreement in the interpretation of oligoclonal bands
- A new founder BRCA1 haplotype identified in the Puglia region is associated with a specific age-related cancer onset in three unrelated families
- Predictive values of D-dimer for adverse pregnancy outcomes: a retrospective study
- A very uncommon haemoglobin value resulting from a severe acute malnutrition in a 16-month-old child in Ethiopia
- Ionized calcium measurements during continuous renal replacement therapy with regional citrate anticoagulation
- The hairy cell leukaemia oxymoron: monocytotic monocytopenia
- Perchlorate interference with electrolyte analysis
- False decrease in serum triglyceride and cholesterol due to massive ascorbate in a bowel preparation solution
