Sysmex UF-100 Research Articles

Road to automated urinalysis analyzer: Validation of Sysmex UN-3000 to supplant manual urinalysis

Abstract Introduction/Objective Traditionally, urinalysis encompasses the chemical analysis of urine by dipstick and manual microscopy for formed elements. High specimen volume and varying subjectivity among individuals performing microscopic analysis make the practice both imprecise and inefficient. Implementation of Sysmex UN- Series™Automated Urinalysis (Sysmex Corporation, Kobe, Japan) fulfilled our need for automation, addressing both issues at hand. Automated urinalysis offers a solution for laboratories to meet the growing demand for faster result turn around times(TAT) with ever increasing specimen volumes. We expect greater sensitivity and reproducibility in terms of comparison to manual microscopy, as well as quicker TAT with the change in methodology. Methods/Case Report Using both unpreserved and preserved urine tubes, a macroscopic comparative study between Clinitek Advantus(manual) and Clinitek Novus (automated) methods was carried out on 141 urines with greater than 60 abnormal patients. Similarly, a microscopic study between the laboratory’s manual microscopy procedure and the Sysmex UF-5000 was carried out on 112 urines with greater than 60 abnormal patients. RBCs, WBCs, Epithelial cells were evaluated under high power field(40X); casts and crystals were evaluated under lower power field(10X). The Reference Range Interval for both chemical and microscopic was verified using 44 normal patient specimens. The quantified values are converted to high and low power field (hpf/lpf), analogous to the current system in the laboratory. Results (if a Case Study enter NA) Most parameters had >90% agreement between manual and automated method. Parameters falling below 90% were checked to see if discrepancies fell within 1 degree. Automated system is more sensitive than manual and our average TAT for urinalysis dropped 50%. Conclusion The automated urinalysis technology enabled us to focus only on samples requiring intervention based on pathological criteria, resulting in reduced overall TAT and workload burden, and improved consistency in reporting across specimens.

B-006 Use of Sysmex UN-3000 Research Parameters for Semiquantitative Analysis of Urine Microscopic Elements

Abstract Background Microscopic examination of urine is an important component of urine analysis. However, it is labor-intensive and requires a skilled microscopist. The Sysmex UN-3000 (Kobe, JP) combines a Siemens CLINITEK Novus (Munich, GER) with a Sysmex UF-5000 flow cytometer and Sysmex UD-10 digital imaging device for fully automated urine analysis. It is FDA-approved for quantitation of red and white blood cells, epithelial cells, casts, and bacteria. It also flags for other particles such as sperm, yeast, pathologic casts, and crystals, which can then be confirmed on the UD-10. We sought to determine if and how the UF-5000 research parameter results could be used for semi-quantitative grading of pathologic casts, squamous epithelial cells, non-squamous epithelial cells, and crystals to match our reporting system. Methods Urine samples were analyzed by the UN-3000 and by manual review of urine sediment per laboratory protocols. Epithelial cells and crystals grades were none seen, few, moderate, many. Cast grades were 0, 1-3, 4-10, and >10. Results of manual microscopy were used to determine numerical cutoffs for the UF-5000 results which would agree within one grade in ≥90% of samples. Sperm and yeast are reported as either present or absent. For these particles, manual microscopy was compared to the results of the UF-5000 flagging and subsequent review of the UD-10 images. Results Rate of agreement between the methods is shown in the table. For sperm the UN-3000 showed 91.7% sensitivity and 100% specificity; for yeast, 93.8% sensitivity and 97.7% specificity. Conclusions We were able to use the research parameters from the UF-5000, in conjunction with the UD-10, to perform semi-quantitative grading. Adoption of this analyzer increases automation, with 70% of samples auto-validating per our protocols, while still conforming to our previous reporting system.

Enhancing clinical decision-making: Sysmex UF-5000 as a screening tool for bacterial urinary tract infection in children.

A rapid screening test for urinary tract infections (UTIs) in children is needed to avoid unnecessary cultures and provide prompt reports to make appropriate clinical decisions. We have evaluated for the first time the performance of the Sysmex UF-5000 flow cytometer as a screening tool for UTIs in children. This study included 4445 pediatric patients, with urinary sediment and urine culture data collected from January 2020 to September 2023. The Sysmex UF-5000 analyzer was utilized to measure urine white blood cell (WBC) and bacteria (BACT), with the findings being compared to the culture results. At ≥ 104 colony-forming unit (CFU)/mL, 513 samples were culture-positive (400 samples presented 104-105 CFU/mL, and 113 demonstrated ≥ 105 CFU/mL bacterial growth). Optimal indicators for positive cultures were BACT counts of 92.2/μL (AUC: 0.944) and WBC counts of 40.8/μL (AUC:0.863). False negative rate were 0.9% when using a 7.8 bacteria/μL cut-off and avoiding unnecessary cultures in 28.1%. The UF-5000 has a higher consistency rate for Gram-negative (GN) bacteria (90.3%) than Gram-positive (GP) bacteria (86.8%). For samples with 105 CFU/mL, UF-5000's Bacteria -Information flags showed superior concordance for samples with 104-105 CFU/mL bacteria. Screening pediatric urine cultures with the UF-5000 showed potential application value in identifying negative cultures and significant bacterial growth, although performance may vary depending on the study population. Furthermore, detecting Gram typing aids in guiding early clinical empirical medication, particularly for UTIs caused by GN bacteria.

The UF-5000 Atyp.C parameter is an independent risk factor for bladder cancer

Bladder carcinoma (BC) accounts for > 90% of all urothelial cancers. Pathological diagnosis through cytoscopic biopsy is the gold standard, whereas non-invasive diagnostic tools remain lacking. The “Atyp.C” parameter of the Sysmex UF-5000 urine particle analyzer represents the ratio of nucleus to cytoplasm and can be employed to detect urinary atypical cells. The present study examined the association between urinary Atyp.C values and BC risk. This two-center, retrospective case–control study identified clinical primary or newly recurrent BC (study period, 2022–2023; n = 473) cases together with controls with urinary tract infection randomly matched by age and sex (1:1). Urinary sediment differences were compared using non-parametric tests. The correlations between urinary Atyp.C levels and BC grade or infiltration were analyzed using Spearman’s rank correlation. The BC risk factor odds ratio of Atyp.C was calculated using conditional logistic regression, and potential confounder effects were adjusted using stepwise logistic regression (LR). Primary risk factors were identified by stratified analysis according to pathological histological diagnosis. The mean value of urinary Atyp.C in BC cases (1.30 ± 3.12) was 8.7 times higher than that in the controls (0.15 ± 0.68; P < 0.001). Urinary Atyp.C values were positively correlated with BC pathological grade and invasion (r = 0.360, P < 0.001; r = 0.367, P < 0.001). Urinary Atyp.C was an independent risk factor for BC and closely related with BC pathological grade and invasion. Elevated urinary Atyp.C values was an independent risk factor for BC. Our findings support the use of Atyp.C as a marker that will potentially aid in the early diagnosis and long-term surveillance of new and recurrent BC cases.

The performance of a Fully Automated Urine Particle Analyzer, Sysmex UF-5000, in detecting fastidious bacteria in urine samples

Several types of fastidious bacteria can cause tract infections. We evaluated the performance of counting fastidious bacteria using a Fully Automated Urine Particle Analyzer UF-5000. The results showed that UF-5000 counts fastidious bacteria in urine without the need for culture using measurement principles based on flow cytometry.

Comparison of the clinical performance of the Atyp.C parameter of the UF-5000 fully automated urine particle analyzer with that of microscopic urine sediment analysis

a) ObjectivesUrinalysis is one of the most common laboratory screening tests to detect problems in the renal and urinary system; however, they cannot detect atypical cells (Atyp.Cs). The Sysmex UF-5000, a fully automated urine particle analyzer, can detect Atyp.Cs via its Atyp.C parameter. This study aimed to compare the clinical value of the Atyp.C parameter with that of urine sediment microscopy. b) MethodA total of 471 leftover urine samples were submitted to the Department of Clinical Laboratory at the University of Tokyo Hospital for urinalysis by manual sediment microscopy examination and UF-5000 Atyp.C analysis. c) ResultOf 471 submitted samples, 117 were positive for Atyp.Cs by urine sediment and 354 samples were negative. The histological subtypes of the Atyp.Cs included 105 cases of suspected urothelial carcinoma cells, 10 suspected squamous carcinoma cells, and 2 of suspected adenocarcinoma cells. The Atyp.C values for the Atyp.C-positive and -negative groups were 2.64 ± 0.69 and 0.38 ± 0.16, respectively. The optimal Atyp.C cutoff value determined by the receiver operating characteristic curve analysis was 0.4/μL. The area under the curve was 0.856, with a sensitivity of 79.5% and specificity of 85.1%. Atyp.C values of the UF-5000 showed high predictive performance for Atyp.C-positive specimens identified by urine sediment microscopy. d) ConclusionsThis study shows that a combination of UF-5000 analysis and microscopic examination of urine sediment improves Atyp.C detection in urine sediment analysis. These results suggest that Atyp.C measured by UF-5000 could be a useful screening parameter in routine testing of urine samples.

Usefulness of UF-5000 automatic screening system in UTI diagnosis.

We have evaluated the Sysmex UF-5000 cytometer use in microbiology for the screening of negative urines, looking for cut-off points to detect bacteria and leukocytes. The number of processed urines was 3569, the highest to date in these studies. The best general cut-off point has been 100 bact/μl, giving an area under the ROC curve of 0.868, a sensitivity of 96%, a specificity of 50%, 1.17% of false negatives, and saving 40% of cultures. The PPV and NPV have been 35.5 and 95.4 respectively. The leukocyte count has not been useful. Finally, we have evaluated urine screening usefulness, concluding that in laboratories such as ours (284 urines/working day) or smaller, it is not cost-effective.

Urine transfer devices may impact urinary particle results: a pre-analytical study.

Well-standardized procedures in the pre-analytical phase of urine diagnostics is of utmost importance to obtain reliable results. We investigated the effect of different urine collection methods and the associated urine transfer tubes on urine test strip and particle results. In total, 146 selected urine samples were subdivided into three different collection containers and subsequently transferred into its accompanying transfer tube (BD, Greiner, Sarstedt vacuum and Sarstedt aspiration). As reference, the original urine sample was directly measured on the analyser. Both chemical test strip analysis (Sysmex UC-3500) and fluorescence flow cytometry particle analysis (Sysmex UF-5000) were performed on all samples. No statistically significant differences in test strip results were found between the studied transfer methods. On the contrary, transfer of urine samples to the secondary tubes affected their particle counts. Clinically significant reductions in counts of renal tubular epithelial cells and hyaline casts were observed using the BD and Greiner transfer tubes and in counts of pathological casts using the BD, Greiner and Sarstedt vacuum tubes. The results of this study indicate that the use of urine transfer tubes may impact counts of fragile urine particles. Clinical laboratories need to be aware about the variation that urine collection methods can induce on urine particle counts.

Accuracy of the Sysmex UF-5000 analyzer for urinary tract infection screening and pathogen classification.

The screening performance of urine flow cytometry parameters (e.g., white blood cell and bacteria) for urinary tract infection (UTI) has been widely recognized. The majority of previous studies, however, investigated the screening performance of Sysmex UF-1000i urine flow cytometer. This study aimed to investigate the screening performance of Sysmex UF-5000 analyzer, a third-generation urinary flow cytometer, for UTI and its novel parameter named Gram flag for discriminating gram-positive and negative pathogens. Urine specimens sent to the clinical microbiology laboratory of our hospital for bacterial culture between September 13, 2021, and November 15, 2021, were prospectively and consecutively collected. The Sysmex UF-5000 analyzer was used to determine urine white blood cell (WBC) and bacteria simultaneously. A chemical strip was used to assess urine nitrate. UTI was defined as positive urine bacterial culture > 104 CFU /ml. The receiver operating characteristics (ROC) curve, nomogram, decision tree, and decision curve were used to determine the screening performance of urine WBC, nitrate, and bacterial. A total of 246 UTIs and 425 non-UTIs were enrolled. The areas under the ROC curve (AUCs) for WBC and bacterial were 0.74 and 0.86, respectively. The decision curve showed that urine bacteria had a higher benefit than WBC. The nomogram indicated that urine bacterial had the largest effect on the probability of UTI. The sensitivity and specificity of the decision tree were 0.69 and 0.95, respectively. The flag of Gram-negative had a positive predictive value (PPV) of 0.93 in patients with urine bacteria > 1367 /μl. Therefore, we conclude that urine bacteria determined by the Sysmex UF-5000 had higher screening performance and greater benefit than WBC. The decision tree can be used to improve the screening performance of routine urinary parameters. The flag of Gram-negative is a reliable indicator to confirm gram-negative bacteria infection in UTI patients.

Evaluation of Sysmex-UF 5000-BF Module for Sterile Body Fluids. An Alternative for Conventional Methods?

Infections of cerebrospinal fluid (CSF), peritoneal and pleural fluids often result in severe morbidity and mortality. Cytometric analysis, cell count, and cell differentiation is supportive in rapid clinical decision. The aim of this study is to evaluate the performance of Sysmex UF-5000 (Sysmex Co., Kobe, Japan) in body fluid (BF) mode for white blood cells and bacterial counting and compare the results with manual microscopy, gram staining, and culture as reference method. A total of 634 body fluid samples (433 CSF, 100 pleural, and 101 peritoneal fluid) submitted to our clinical microbiology laboratory between December 2018 and January 2020 were enrolled in the study. Specimens were analyzed for white blood cell (WBC) counts with Sysmex UF-5000-BF mode. The results were grouped into five categories and compared with the conventional methods as reference method. The relationship between culture results and Sysmex UF5000-BF bacterial load and WBC count were evaluated for the detection of infection. The categorical agreement of UF 5000-BF mode was very strong for CSF (correlation coefficient: 0.70, p < 0.05) and good agreement was found for pleural and peritoneal samples (correlation coefficient: 0.63, p < 0.05). Sensitivity was 100% and specificity was 64% in pleural samples. For ascites sensitivity and specificity were found as 94.1% and 77.4%, and for CAPD samples as 100% and 81,2% respectively. Bacterial and WBC count with flow cytometry was higher among culture positive samples (p < 0.05). The same significant difference was detected between the UF 5000-BF bacterial counts and the samples in which bacteria were detected in the gram preperation (p < 0.05). WBC count by UF-5000-BF was also higher among culture positive compared to culture negative samples (p < 0.05). Our results demonstrated that the flow cytometric method, Sysmex UF-5000 body fluid (BF) mode, can be an alternative particularly in CSF samples. Detection of 100% sensitivity in peritoneal and pleural samples can prevent unnecessary antibiotic treatment and possible resistance development. Besides, automated bacterial counting can be used for rapid prediction of a positive body fluid culture.

Performance Evaluation of Urine Osmolality Measurement on Sysmex UF-5000 and the Effect of Molecules and Particles in Urine.

Urine osmolality determines the concentration ability of the kidney. Therefore, it is used to assess the body's hydration status, electrolyte levels, and acid-base disturbances. We aimed to evaluate the analytical performance of osmolality measurement of the Sysmex UF-5000 (UF-5000), to examine the effect of different molecules and particles in the urine on the osmolality measurement. Complete urinalysis and conductivity-based osmolality analysis with UF-5000 and osmolality analysis with Advanced® Model 3320 Micro-Osmometer (AI-3320) by freezing point reduction method were performed in the urine samples. Samples were grouped as negative, glucosuria, proteinuria, hematuria, pyuria, crystalluria, and urobilinogen. Total impressions were calculated as < 5% and accuracy values were < 1.66% in both analyzers. The regression equation was found to be y = -12.54 + 0.956x and the relative difference between the analyzers was 8.7% in 586 samples. When patients with Glucose > 2+ were excluded the regression equation of 507 samples was found as y = 5.10 + 0.948x and the relative difference was 4.6%. The percentages of samples with a difference greater than the allowable difference were 18.8%, 11.6%, 35.9%, 13.7%, 18.7%, and < 12.2% in all samples, all samples without glucosuria > 2+, glucosuria, glucosuria < 3+, proteinuria, and other subgroups, respectively. Considering the good accessibility of the automated routine complete urine analyzer, UF-5000 can be considered to determine whether urine osmolality is within reference or should be measured by methods based on colligative properties. Thus, referral of patients to a clinic that uses the colligative measurement method may be used more effectively.

The diagnostic value of rapid urine test platform UF-5000 for suspected urinary tract infection at the emergency department.

Background and objectiveUrine culture is time consuming, which may take days to get the results and impede further timely treatment. Our objective is to evaluate whether the fast urinalysis and bacterial discrimination system called Sysmex UF-5000 may predict urinary tract infections (UTIs) (within minutes) compared with the clinical routine test in suspected UTI patients. In addition, we aimed to explore the accuracy of microbiologic information by UF-5000.Materials and MethodsConsecutive patients who were admitted from the emergency department at Queen Mary Hospital (a tertiary hospital in Hong Kong) from June 2019 to February 2020 were enrolled in the present study. The dipstick test, manual microscopic test with culture, and Sysmex UF-5000 test were performed in the urine samples at admission.ResultsA total of 383 patients were finally included in the present study. UF-5000 urinalysis (area under the receiver operator characteristic curve, AUC=0.821, confidence interval, 95%CI: 0.767–0.874) outperformed the dipstick test (AUC=0.602, 95%CI: 0.550–0.654, P=1.32×10-10) for predicting UTIs in patients without prior antibiotic treatment. A significant net benefit from UF-5000 was observed compared with the dipstick test (NRI=39.9%, 95%CI: 19.4–60.4, P=1.36 × 10-4). The urine leukocyte tested by UF-5000 had similar performance (AUC) for predicting UTI compared with the manual microscopic test (P=0.27). In patients without a prior use of antibiotics, the concordance rates between UF-5000 and culture for predicting Gram-positive or -negative bacteriuria and a negative culture were 44.7% and 96.2%, respectively.ConclusionsUF-5000 urinalysis had a significantly better predictive value than the dipstick urine test for predicting UTIs.

Consistency analysis of the Sysmex UF-5000 and Atellica UAS 800 urine sedimentation analyzers.

ObjectiveTo evaluate the consistency between the results of Sysmex UF‐5000 system and Atellica® UAS 800 Urine Sediment Analyzer.MethodsA total of 636 random urine samples were collected from inpatients and outpatients from March to September 2021. Urine was collected for analysis by the Sysmex UF‐5000, Atellica UAS 800 systems, and manual microscopic examination. The results of manual microscopy as the gold standard, the coincidence rate and false‐negative rate of Sysmex UF‐5000 and Atellica UAS 800 systems in the detection of red blood cells, white blood cells, and casts were calculated.ResultsThe coincidence rates of red blood cells, white blood cells, and cast, crystals, and other sediment components for the Sysmex UF‐5000 system were 85.37%, 87.89%, 91.67%, 88.36%, and 71.86%. The false‐negative rates were 28.47%, 3.75%, 68.97%, 37.25%, and 30.63%. The coincidence rates of red blood cells, white blood cells, and cast, crystals, and other sediment components for the Atellica UAS 800 system were 85.06%, 90.25%, 59.12%, 91.67%, and 67.45% and the false‐negative rates were 60.42%, 21.25%, 36.21%, 19.64%, and 35.80%.ConclusionTwo instruments are superior in the detection of red blood cells and white blood cells. The Atellica UAS 800 system with image review has a good coincidence rate in the identification of crystals and casts. The identification of various sediment components in urine by both instruments meets the laboratory requirements. Two instruments with different methodologies have their own characteristics, and we should reasonably use them according to the conditions of the laboratory.

Comparison of Laboratory Diagnosis of Urinary Tract Infections Based on Leukocyte and Bacterial Parameters Using Standardized Microscopic and Flow Cytometry Methods

Background Rapid and reliable tests are essential for the diagnostic laboratory confirmation of urinary tract infections (UTIs). Until now, UTI has been confirmed by the microbiology culture of urine, requiring at least 48-hour turnaround time (TAT), with a standardized microscopic method being widely favored. Automated urine flow cytometry, however, has recently been used to improve the rapid TAT by analyzing the urine sediment. This study therefore aimed to compare the diagnostic value of the Shih-Yung conventional microscopic and urine flow cytometry methods in the detection of leukocyte and bacterial parameters of patients with UTIs in an outpatient clinic. Methods A cross-sectional study was conducted on a total of 100 patients. Seventy urine samples were positive for leukocytes and nitrite chemistry, and 30 were negative for both. The measurements of urine leukocytes and bacteria were compared between Sysmex UF-5000 urine flow cytometry and the Shih-Yung method. The diagnostic value was obtained from ROC analysis of urine flow cytometry and the culture. Results A leukocyte cutoff value of 87.2/μL had a sensitivity and specificity of 98.33% and 95%, respectively, and 98.33% sensitivity and 75% specificity at a bacterial cutoff of 582.22/μL. Interestingly, our study identified strong and consistent agreement of leukocyte and bacterial parameters between urine flow cytometry and Shih-Yung (k = 0.959, p < 0.001 and k = 0.939, p < 0.001, respectively). Furthermore, through analyzing the dominance angle of the scattergram, a strong agreement was obtained with the culture result (k = 0.880, p < 0.001). Conclusions The Shih-Yung method showed consistent agreement with urine flow cytometry for the detection of leukocytes and bacteria. The use of certain cutoffs for bacterial and leukocyte parameters in urine flow cytometry demonstrated very good performance in detecting acquired symptomatic UTIs.

Comparison study to evaluate analytical performances of AUTION EYE AI-4510, Atellica UAS800, and Sysmex UF-5000, considering their availability for holiday/night medical services

Comparison study to evaluate analytical performances of AUTION EYE AI-4510, Atellica UAS800, and Sysmex UF-5000, considering their availability for holiday/night medical services

Comparison of sysmex UF-5000 flow cytometer and fuchs-rosenthal chamber urine sediment analysis

Comparison of sysmex UF-5000 flow cytometer and fuchs-rosenthal chamber urine sediment analysis

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.

IntroductionUrinary 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.HypothesisAdding 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.AimWe 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.MethodologyWe 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.ResultsROC 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 %.ConclusionFlow 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.

Rapid diagnosis and reduced workload for urinary tract infection using flowcytometry combined with direct antibiotic susceptibility testing.

We evaluated if flowcytometry, using Sysmex UF-5000, could improve diagnosis of urinary tract infections by rapid identification of culture negative and contaminated samples prior to culture plating, thus reducing culture plating workload and response time. We also evaluated if it is possible to reduce the response time for antibiotic susceptibility profiles using the bacteria information flag on Sysmex UF-5000 to differentiate between Gram positive and negative bacteria, followed by direct Antibiotic Susceptibility Testing (dAST) on the positive urine samples. One thousand urine samples were analyzed for bacteria, white blood cells and squamous cells by flowcytometry before culture plating. Results from flowcytometric analysis at different cut-off values were compared to results of culture plating. We evaluated dAST on 100 urine samples that were analyzed as positive by flowcytometry, containing either Gram positive or Gram negative bacteria. Using a cut-off value with bacterial count ≥100.000/mL and WBCs ≥10/μL, flowcytometry predicted 42,1% of samples with non-significant growth. We found that most contaminated samples contain few squamous cells. For 52/56 positive samples containing Gram negative bacteria dAST was identical to routine testing. Overall, there was concordance in 555/560 tested antibiotic combinations. Flowcytometry offers advantages for diagnosis of urinary tract infections. Screening for negative urine samples on the day of arrival reduces culture plating and workload, and results in shorter response time for the negative samples. The bacteria information flag predicts positive samples containing Gram negative bacteria for dAST with high accuracy, thus Antibiotic Susceptibility Profile can be reported the day after arrival. For the positive samples containing Gram negative bacteria the concordance was very good between dAST and Antibiotic Susceptibility Testing in routine. For positive samples containing Gram positive bacteria the results were not convincing. We did not find any correlation between epithelial cells and contamination.

Evaluation of the sysmex UF-5000 fluorescence flow cytometer as a screening platform for ruling out urinary tract infections in elderly patients presenting at the Emergency Department

In this study, we evaluated the performance of the flow cytometer-based Sysmex UF-5000 automated urine analyzer as a screening tool for ruling out urinary tract infections in elderly patients presenting at the emergency department. A total of 1119 unselected patient samples (including 544 samples from elderly patients) submitted for urine culture were included in this study. Samples were measured on UF-5000 and dipsticks and the results were compared with interpretation of culture results, which is the gold standard. We obtained a diagnostic sensitivity of 99% and specificity of 51% with a low rate of false negatives (0.2%) and a negative predictive value of 99% at 108 colony forming bacteria/L (CFB/L). A bacterial count ≥ 50x106/L or yeast like cells ≥ 25x106/L was used as the cutoff value. At this cutoff value, 30% of the urine cultures would have been redundant. This resulted in 35% false positive samples, mainly due to particle contamination or nongrowing bacteria. In comparison, at best, the dipsticks have a diagnostic sensitivity of 89%, a specificity of 52% and a negative predictive value of 92% at 108 CFB/L.

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

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. 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. Overall 98/344 (28.5%) samples were urine culture positive at a cut-off of≥105CFU/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%). 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.