Erratum to: A new concept and a comprehensive evaluation of SYSMEX UF-1000i flow cytometer to identify culture-negative urine specimens in patients with UTI

Monsen, T.; Ryden, Patrik

doi:10.1007/s10096-017-3059-8

Cited by 3 publications

(4 citation statements)

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“…The gold standard test to diagnose UTIs is the urine culture. However, the concentration of positive urine culture with the diagnostic criteria is still a matter to debate [7][8][9]. In this study, bacilli > 10 5 cfu/mL or cocci > 10 4 cfu/mL with one or two significant pathogens as the positive results of urine culture.…”

Section: Discussionmentioning

confidence: 83%

The Diagnostic Performance of Urine Flow Cytometer UF1000i for Urinary Tract Infections

Sun¹,

Zuo²,

Liu³

et al. 2018

Clin. Lab.

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Background: Urinary tract infections (UTIs) are one of the most common infectious diseases in clinic. Urine flow cytometry is receiving more and more attention due to its rapid forecast of UTIs. Methods: The Urine Flow Cytometer UF1000i has a series of software programs to quantify bacteria (BACT) and white blood cells (WBC), and describe the scatter diagram of bacteria. The UTIs were predicted based on the cutoff values with the Receiver Operating Characteristic (ROC) curves of BACT and WBC counts. To evaluate the diagnostic performance of UF1000i for UTIs, the sensitivity and specificity of 889 urine samples were determined in comparison to the results of urine culture. Meanwhile the bacterial morphology indication of the UF1000i was evaluated in order to help doctors choose antibiotics. The angle of the scatter cloud with the x-axis was used to classify the infected bacteria as bacilli (< 30°) or cocci (≥ 30°). Results: The best cutoff value of BACT counts for predicting UTIs was 119 per µL, and the sensitivity and specificity were 95.5% and 88.7%, respectively. While the best cutoff value of WBC counts was 81.5 per µL, and the sensitivity and specificity were 77.6% and 76.7%, respectively. In addition, the best cutoff values for females were 583 BACT per µL and 137.5 WBC per µL. They were much higher than for males (118 BACT per µL and 91 WBC per µL). The coincidence of the bacterial morphology information between the UF1000i software indication and the bacterial actual morphology identified by urine culture was 83% (bacilli) and 68% (cocci), respectively. Conclusions: Data demonstrated that the performance of BACT counts for UTIs is superior to WBC counts. In addition, the bacterial morphology could preliminarily be predicated by the scatter diagram. Since the urine flow cytometer UF1000i can provide the data of both BACT counts and the scatter diagram, the urine flow cytometry was regarded as a suitable method for screening UTIs. Moreover, it would be better to take gender into consideration when setting the best cutoff value for diagnosis of UTIs in clinic.

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Section: Discussionmentioning

confidence: 83%

The Diagnostic Performance of Urine Flow Cytometer UF1000i for Urinary Tract Infections

Sun¹,

Zuo²,

Liu³

et al. 2018

Clin. Lab.

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“…According to the literature, both Gram-positive and Gram-negative bacteria are reported among false negative samples [4,14,23,24]. We initially identified 96 false negative samples in this study, when using only the bacterial count parameter (Table 5).…”

Section: Discussionmentioning

confidence: 99%

Use of Sysmex UF-5000 flow cytometry in rapid diagnosis of urinary tract infection and the importance of validating carryover rates against bacterial count cut-off

Haugum

Haugan

Skage

et al. 2021

Journal of Medical Microbiology

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Introduction. Urinary tract infections are common bacterial infections worldwide. Urine culture is the gold standard method to identify and quantify the presence or absence of bacteria in urine. Flow cytometry, which can differentiate and quantify multiple particles (including bacteria) in the urine, presents an alternative method for rapid screening to rule out bacteriuria. Hypothesis. Adding flow cytometry to identify urine samples without bacteriuria could substantially reduce the number of urine samples that need to be cultured as well as the response time for negative results. However, the level of instrument rinsing between samples could affect sample-to-sample carryover rate, a concept given little attention in previous studies. Aim. We aimed to evaluate urine flow cytometry as a rapid screening method to identify urine samples without significant bacterial growth, including analyses of cross-contamination and sample-to-sample carryover rate. Methodology. We analysed 3919 urine samples by quantitative urine culture and flow cytometry screening (Sysmex UF-5000). Receiver operator characteristic (ROC) curve analyses were used to test method agreement to identify: (a) positive vs. negative culture and (b) mixed vs. pure culture. In addition, we performed carryover and cross-contamination studies. Results. ROC curve analyses identified bacterial count (BACT ml−1) and leucocyte count (WBC µl−1) as possible predictors of bacterial growth in the total material and subpopulations, except pregnant women (n=451). This subgroup was excluded from further analyses, leaving a final 3468 urine samples. Area under the ROC curve was 0.94 (95 % CI 0.93–0.95) and 0.81 (95 % CI 0.79–0.82) for bacterial and leucocyte count, respectively. A bacterial count cut-off of 30 BACT ml−1 resulted in 95.2 % sensitivity and 91.2 % negative predictive value, resulting in approximately 30 % of urine samples that could be reported as negative without culture. Use of high-level rinse modes was necessary to ensure carryover rates <0.05 %. Conclusion. Flow cytometry is a suitable and rapid method to rule out urine samples without significant bacterial growth. Rinses between samples should be adjusted, depending on the cut-off used, to prevent sample-to-sample carryover, whereas cross-contamination can be eliminated by the use of separate urine aliquots for flow cytometry analysis and urine culturing respectively.

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“…A meta-analysis by Shang et al [5] with 19 studies comprising 22,305 samples calculates screening performance as follows: 0.92 SE, 0.60 SP for UTI screening when using bacterial counts, 0.87 SE, and 0.67 SP when using leukocyte counts as surrogate. It seems problematic that data in this meta-analysis were pooled from studies using different reference standards (>10 3 , >10 4 and >10 5 CFU/ mL). Our data for >10 5 CFU/mL correspond well -reaching 0.93 SE and 0.92 SP -whereas data for the lower cutoff of >10 4 CFU/mL were less accurate, showing a SE of 0.78 and a SP of 0.91.…”

Section: Discussionmentioning

confidence: 99%

“…The reliability of this approach is an ongoing subject of discussion [ 3 ]. In recent years, urine flow cytometry (UFC) has been evaluated as a reliable and efficient method to diagnose bacteriuria, revealing heterogeneous results in different patient populations [ 4 , 5 , 6 ]. Patients scheduled for surgery are of particular interest, as asymptomatic bacteriuria is of relevance in urothelium-traumatizing urological procedures [ 1 ].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Urine Flow Cytometry on the UF-1000i System and Urine Culture of Urine Samples from Urological Patients

et al. 2021

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Introduction: The aims of this study were to evaluate urine flow cytometry (UFC) as a tool to screen urine samples of urological patients for bacteriuria and to compare UFC and dipstick analysis with urine culture in a patient cohort at a urological department of a university hospital. Methods and Material: We screened 662 urine samples from urological patients (75.2% male; 80.7% inpatients; mean age 58 years). UFC results were compared to microbiological urine culture. Results: The accuracy in using the UFC-based parameters for detecting cultural bacteriuria was 91.99% and 88.97% for ≥105 colony-forming units (CFU)/mL and ≥104 CFU/mL, respectively. UFC and leukocyte dipstick analysis measured leukocyturia similarly (Pearson correlation coefficient 0.87, p value <0.01%), but dipstick analysis scored less accurately on bacteriuria (accuracy 59.37% and 62.69%). UFC remained effective in subgroup analysis of patients of both sexes and with different urological conditions with its overall use only slightly impaired when assessing gross hematuria (NPV 84.62% for ≥104 CFU/mL). UFC also reliably removed those urine samples below cutoffs with negative predictive values of 99.28% for ≥105 CFU/mL and 95.86% for ≥104 CFU/mL. Conclusion: Counting bacteria with UFC is an accurate and rapid method to determine significant bacteriuria in urological patients and is superior to dipstick analysis or indirect surrogate parameters such as leukocyturia. When UFC is available, we recommend it to be used for the diagnosis of bacteriuria over findings obtained by dipstick analysis.

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Erratum to: A new concept and a comprehensive evaluation of SYSMEX UF-1000i flow cytometer to identify culture-negative urine specimens in patients with UTI

Cited by 3 publications

References 0 publications

The Diagnostic Performance of Urine Flow Cytometer UF1000i for Urinary Tract Infections

The Diagnostic Performance of Urine Flow Cytometer UF1000i for Urinary Tract Infections

Use of Sysmex UF-5000 flow cytometry in rapid diagnosis of urinary tract infection and the importance of validating carryover rates against bacterial count cut-off

Comparison of Urine Flow Cytometry on the UF-1000i System and Urine Culture of Urine Samples from Urological Patients

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