Comparison of three automated urinalysis systems--Bayer Clinitek Atlas, Roche Urisys 2400 and Arkray Aution Max for testing urine chemistry and detection of bacteriuria

Advances in Microfluidic Paper-Based Analytical Devices (µPADs): Design, Fabrication, and Applications

Microfluidic Paper-based Analytical Devices (µPADs) have emerged as a new class of microfluidic systems, offering numerous advantages over traditional microfluidic chips. These advantages include simplicity, cost-effectiveness, stability, storability, disposability, and portability. As a result, various designs for different types of assays are developed and investigated. In recent years, µPADs are combined with conventional detection methods to enable rapid on-site detection, providing results comparable to expensive and sophisticated large-scale testing methods that require more time and skilled personnel. The application of µPAD techniques is extensive in environmental quality control/analysis, clinical diagnosis, and food safety testing, paving the way for on-site real-time diagnosis as a promising future development. This review focuses on the recent research advancements in the design, fabrication, material selection, and detection methods of µPADs. It provides a comprehensive understanding of their principles of operation, applications, and future development prospects.

Application of analytical performance specifications for urine test strip methods: Importance of reflectance signals

INTRODUCTION

Urinalysis is essential for diagnosing kidney-related medical conditions. Urine test strip analysis serves as an initial and efficient screening method for reflex testing with accurate quantitative methods.

MATERIALS AND METHODS

Freshly voided urines (n = 206) were analysed using two urine test strip brands on UC-MAX (Menarini) and cobas u 601 (Roche Diagnostics) instruments. Ordinal scale categories and reflectance signals (if available) were both used for the comparison with reference quantitative methods for glucose, proteins and albumin (cobas 503). Samples were considered positive when glucose > 15 or ≥ 54 mg/dL, proteins ≥ 200 mg/L and albumin ≥ 10 mg/L. Optimized reflectance thresholds were calculated by ROC curve analysis. Analytical performance specifications (APS) for trueness of test strip were gathered from the EFLM guideline (FPD, FNG, FNC).

RESULTS

Reflectance signals were significantly lower in urine samples considered positive by the reference method (p < 0.0001). Reflectance signals were also correlated with quantitative measurements, showing strong correlation (0.754 to 0.969). Only the use of optimized reflectance thresholds on cobas u 601 achieved at least the minimum EFLM APS (FPD < 20%, FNG < 50% and FNC < 10%).

CONCLUSION

The use of reflectance signals from urine test strips enhanced accuracy for glucose, proteins, and albumin measurement and may contribute to improve diagnosis of diverse kidney-related conditions.

Evaluation of the Atellica® UAS 800: a new member of the automated urine sediment analyzer family

BACKGROUND

In 2017 the Atellica^® UAS 800 urine sediment analyzer was introduced by Siemens Healthineers. We investigated its applicability in the standardization and automation of the laboratory urinalysis workflow, including the prediction of urine culture outcome and glomerular pathology.

METHODS

We evaluated the performance characteristics of the Atellica^® UAS 800 and its correlation with the iQ200 (Beckman Coulter). In addition, we studied the agreement between Atellica^® UAS 800 and CLINITEK Novus^® and determined the predictive value of bacteria and leukocyte counts for urine culture outcome. Furthermore, we investigated the ability of Atellica^® UAS 800 to identify pathological casts and dysmorphic erythrocytes in comparison to manual microscopy.

RESULTS

Erythrocyte and leukocyte analyses indicated high intra- and inter-run precisions and good correlations with the iQ200. We found that the Atellica^® UAS 800 detects bacteria with higher sensitivity than the iQ200. The Atellica^® UAS 800 and CLINITEK Novus^® showed a high degree of conformity. We determined seven combinations of clinical cut-off values of bacteria and leukocytes for predicting urine culture outcome with sensitivity, specificity, and negative predictive values of 95%, 52%, and 93%, respectively. Using the Atellica^® UAS 800, hyaline casts, erythrocyte casts, leukocyte casts, and dysmorphic erythrocytes were correctly recognized in 76%, 22%, 2%, and 39% of the samples, respectively.

CONCLUSIONS

The Atellica^® UAS 800 is a robust, fast, and user-friendly analyzer, which accurately quantifies erythrocytes, leukocytes, bacteria and squamous epithelial cells, and may be utilized for predicting positive urine cultures. The detection of clinically important pathological casts and dysmorphic erythrocytes proved insufficient.

Comparison of five automated urine sediment analyzers with manual microscopy for accurate identification of urine sediment

Background While the introduction of automated urine analyzers is expected to reduce the labor involved, turnaround time and potential assay variations, microscopic examination remains the "gold standard" for the analysis of urine sediments. In this study, we evaluated the analytical and diagnostic performance of five recently introduced automated urine sediment analyzers. Methods A total of 1016 samples were examined using five automated urine sediment analyzers and manual microscopy. Concordance of results from each automated analyzer and manual microscopy were evaluated. In addition, image and microscopic review rates of each system were investigated. Results The proportional bias for red blood cells (RBCs), white blood cells (WBCs) and squamous epithelial cells in the automated urine sediment analyzers were within ±20% of values obtained using the manual microscope, except in the cases of RBCs and WBCs analyzed using URiSCAN PlusScope and Iris iQ200SPRINT, respectively. The sensitivities of Roche Cobas® u 701 and Siemens UAS800 for pathologic casts (73.6% and 81.1%, respectively) and crystals (62.2% and 49.5%, respectively) were high, along with high image review rates (24.6% and 25.2%, respectively). The detection rates for crystals, casts and review rates can be changed for the Sysmex UF-5000 platform according to cut-off thresholds. Conclusions Each automated urine sediment analyzer has certain distinct features, in addition to the common advantages of reducing the burden of manual processing. Therefore, laboratory physicians are encouraged to understand these features, and to utilize each system in appropriate ways, considering clinical algorithms and laboratory workflow.

Diaper-embedded urine test device for the screening of urinary tract infections in children: a cohort study

BACKGROUND

There is a need for an easy and sensitive method for screening of urinary tract infections in young children. We set out to test whether a novel diaper-embedded urine test device is feasible and reliable in screening for urinary tract infections.

METHODS

This prospective cohort study consisted of young children examined due to a suspected acute urinary tract infection at the Pediatric Emergency Department of the Oulu University Hospital, Finland. We analyzed the same urine samples using three different methods: 1) a diaper-embedded test device applied to the urine pad within the diaper, 2) a urine sample aspirated from the urine pad for the conventional point-of-care dipstick test, and 3) a urine sample aspirated from the urine pad and analyzed in the laboratory with an automated urine chemistry analyzer. The gold standard for confirming urinary tract infection was quantitative bacterial culture.

RESULTS

Urine samples were available from 565 children. Bacterial culture confirmed urinary tract infection in 143 children. Sensitivity of the positive leukocyte screening of the diaper-embedded urine test device was 93.1% (95% CI: 87.4-96.8) and that of the point-of-care urine dipstick analysis was 95.4% (90.3-98.3) in those with both tests results available (n = 528). The sensitivity of the positive leukocyte test of the diaper-embedded test device was 91.4% (85.4-95.5) and that of the automated analysis was 88.5% (82.0-93.3) in those with both tests available (n = 547). The time to the test result after urination was immediate for the diaper-embedded test, 1-5 min for point-of-care dipstick, and 30-60 min for laboratory-based automated urine chemistry analyzer.

CONCLUSIONS

In this prospective study, the diaper-embedded urine test device was an easy and sensitive screening method for UTIs in young children. The main clinical benefit of the diaper-embedded urine test device was that the screening test result was available immediately after urination.

Comparing Two Automated Techniques for the Primary Screening-Out of Urine Culture

Urinary tract infection is the most common human infection with a high morbidity. In primary care and hospital services, conventional urine culture is a key part of infection diagnosis but results take at least 24 h. Therefore, a rapid and reliable screening method is still needed to discard negative samples as quickly as possible and to reduce the laboratory workload. In this aspect, this study aims to compare the diagnostic performance between Sysmex UF-1000i and FUS200 systems in comparison to urine culture as the gold standard. From March to June 2016, 1,220 urine samples collected at the clinical microbiology laboratory of the “Miguel Servet” hospital were studied in parallel with both analysers, and some technical features were evaluated to select the ideal equipment. The most balanced cut-off values taking into account bacteria or leukocyte counts were 138 bacteria/μL or 119.8 leukocyte/μL for the UF-1000i (95.3% SE and 70.4% SP), and 5.7 bacteria/μL or 4.3 leukocyte/μL for the FUS200 (95.8% SE and 44.4% SP). The reduction of cultured plates was 37.4% with the FUS200 and 58.3% with the UF-1000i. This study shows that both techniques improve the workflow in the laboratory, but the UF-1000i has the highest specificity at any sensitivity and the FUS200 needs a shorter processing time.

Performance Evaluation and Comparison of the Fully Automated Urinalysis Analyzers UX-2000 and Cobas 6500

OBJECTIVE

To evaluate and compare the performances of the automated urinalysis devices UX-2000 and Cobas 6500.

METHOD

A total of 258 urine specimens were collected from the routine specimen workload. We analyzed all specimens on both automated instruments and recorded the turnaround time from each method. Physical, chemical, and sedimentary urine components were compared between the automated and the manual method for each analyzer.

RESULTS

The correlation of urine physical/chemical properties between the 2 instruments was excellent. The Cobas 6500 instrument demonstrated a higher level of agreement for red blood cells (Cobas 6500:R= 0.94; UX-2000:R= 0.78) and white blood cells (Cobas 6500:R= 0.95; UX-2000:R= 0.85). The UX-2000 demonstrated higher sensitivity for small round cells, hyaline casts, pathological casts, and bacteria. The median turnaround time was 1.5 minutes and 8.5 minutes for the Cobas 6500 and UX-2000, respectively.

CONCLUSIONS

The 2 devices showed similar performance in technical evaluation; they each reduce workload and increase time saving. However, manual examination by technicians is recommended for pathological specimens.

Prospective, observational study comparing automated and visual point-of-care urinalysis in general practice

OBJECTIVE

Point-of-care testing (POCT) urinalysis might reduce errors in (subjective) reading, registration and communication of test results, and might also improve diagnostic outcome and optimise patient management. Evidence is lacking. In the present study, we have studied the analytical performance of automated urinalysis and visual urinalysis compared with a reference standard in routine general practice.

SETTING

The study was performed in six general practitioner (GP) group practices in the Netherlands. Automated urinalysis was compared with visual urinalysis in these practices. Reference testing was performed in a primary care laboratory (Saltro, Utrecht, The Netherlands).

PRIMARY AND SECONDARY OUTCOME MEASURES

Analytical performance of automated and visual urinalysis compared with the reference laboratory method was the primary outcome measure, analysed by calculating sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) and Cohen's κ coefficient for agreement. Secondary outcome measure was the user-friendliness of the POCT analyser.

RESULTS

Automated urinalysis by experienced and routinely trained practice assistants in general practice performs as good as visual urinalysis for nitrite, leucocytes and erythrocytes. Agreement for nitrite is high for automated and visual urinalysis. κ's are 0.824 and 0.803 (ranked as very good and good, respectively). Agreement with the central laboratory reference standard for automated and visual urinalysis for leucocytes is rather poor (0.256 for POCT and 0.197 for visual, respectively, ranked as fair and poor). κ's for erythrocytes are higher: 0.517 (automated) and 0.416 (visual), both ranked as moderate. The Urisys 1100 analyser was easy to use and considered to be not prone to flaws.

CONCLUSIONS

Automated urinalysis performed as good as traditional visual urinalysis on reading of nitrite, leucocytes and erythrocytes in routine general practice. Implementation of automated urinalysis in general practice is justified as automation is expected to reduce human errors in patient identification and transcribing of results.

Case report: proximal tubule impairment following volatile anesthetic exposure

The safety of contemporary volatile anesthetic agents with respect to kidney function is well established, and growing evidence suggests that volatile anesthetics even protect against ischemic nephropathy. However, studies examining effects of volatile anesthetics on kidney function frequently demonstrate transient proteinuria and glycosuria following exposure to these agents, although the cause of these findings has not been thoroughly examined. We describe the case of a patient who underwent a neurosurgical procedure, then experienced glycosuria without hyperglycemia that resolved within days. Following a second neurosurgical procedure, the patient again developed glycosuria, now associated with ketonuria. Further examination demonstrated nonalbuminuric proteinuria in conjunction with urinary wasting of phosphate and potassium, indicative of proximal tubule impairment. We suggest that transient proximal tubule impairment may play a role in the proteinuria and glycosuria described following volatile anesthetic exposure and discuss the relationship between these observations and the ability of these agents to protect against ischemic nephropathy.

Performance Evaluation of Three URiSCAN Devices for Routine Urinalysis

BACKGROUND

This study compares the diagnostic performance (in routine urinalysis) of three URiSCAN devices and three Roche analyzers to manual microscopy and quantitative assays.

METHODS

We analyzed eight dipstick tests using three URiSCAN devices. The results were compared to those of the tests performed using three Roche analyzers. The results of leukocyte and erythrocyte screens were compared to those obtained using manual microscopy. Protein, glucose, pH, and specific gravity (SG) assays performed on the URiSCAN devices were compared with the results of corresponding quantitative assays.

RESULTS

The rates of agreement within one grade difference were found to be more than 94.3%. When compared with manual microscopy, the Optima provided better diagnostic performance for the detection of leukocytes compared with the Urisys 1100. Compared to the Urisys 2400, the Super plus provided better diagnostic performance with regard to both leukocytes and erythrocytes. There was good correlation between the three URiSCAN devices and each quantitative assay, except for SG detection.

CONCLUSION

There were well correlated results between those of the three URiSCAN devices and those obtained using the corresponding Roche analyzers, quantitative assays, and manual microscopy. URiSCAN series devices are therefore suitable for routine urinalysis in clinical laboratories.

Analytical performance, agreement and user-friendliness of six point-of-care testing urine analysers for urinary tract infection in general practice

OBJECTIVE

Various point-of-care testing (POCT) urine analysers are commercially available for routine urine analysis in general practice. The present study compares analytical performance, agreement and user-friendliness of six different POCT urine analysers for diagnosing urinary tract infection in general practice.

SETTING

All testing procedures were performed at a diagnostic centre for primary care in the Netherlands. Urine samples were collected at four general practices.

PRIMARY AND SECONDARY OUTCOME MEASURES

Analytical performance and agreement of the POCT analysers regarding nitrite, leucocytes and erythrocytes, with the laboratory reference standard, was the primary outcome measure, and analysed by calculating sensitivity, specificity, positive and negative predictive value, and Cohen's κ coefficient for agreement. Secondary outcome measures were the user-friendliness of the POCT analysers, in addition to other characteristics of the analysers.

RESULTS

The following six POCT analysers were evaluated: Uryxxon Relax (Macherey Nagel), Urisys 1100 (Roche), Clinitek Status (Siemens), Aution 11 (Menarini), Aution Micro (Menarini) and Urilyzer (Analyticon). Analytical performance was good for all analysers. Compared with laboratory reference standards, overall agreement was good, but differed per parameter and per analyser. Concerning the nitrite test, the most important test for clinical practice, all but one showed perfect agreement with the laboratory standard. For leucocytes and erythrocytes specificity was high, but sensitivity was considerably lower. Agreement for leucocytes varied between good to very good, and for the erythrocyte test between fair and good. First-time users indicated that the analysers were easy to use. They expected higher productivity and accuracy when using these analysers in daily practice.

CONCLUSIONS

The overall performance and user-friendliness of all six commercially available POCT urine analysers was sufficient to justify routine use in suspected urinary tract infections in general practice.

Risk of poor outcomes with novel and traditional biomarkers at clinical AKI diagnosis

BACKGROUND AND OBJECTIVES

Studies have evaluated acute kidney injury (AKI) using biomarkers in various settings, but their prognostic utility within current practice is unclear. Thus, we sought to determine the prognostic utility of newer biomarkers or traditional markers (fractional excretion of sodium [FeNa] and urea [FeUrea] and microscopy) over clinical assessment alone.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a prospective cohort study of adults on the first day of meeting AKI criteria. We measured urine concentrations of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and IL-18 and determined FeNa, FeUrea, and microscopy score for casts and tubular cells. Primary outcome was worsened AKI stage from enrollment to peak serum creatinine or in-hospital death.

RESULTS

In 249 recipients, 57% were ≥65 years old, 48% were from intensive care, and mean baseline GFR was 69 ± 30 ml/min per 1.73 m(2). AKI was considered prerenal in 164 (66%), acute tubular necrosis (ATN) in 51 (20%), and "other" in 34 (14%). All mean protein biomarker concentrations, FeNa, FeUrea, and microscopy scores were statistically different between prerenal and ATN. Seventy-two patients (29%) developed the primary outcome. There was an approximate three-fold increase in adjusted risk for the outcome for upper versus lower values of NGAL, KIM-1, IL-18, and microscopy score (P values <0.05). Net reclassification improved after adding these to baseline clinical assessment. FeNa and FeUrea were not useful.

CONCLUSIONS

On the first day of AKI, urine protein biomarkers and microscopy significantly improve upon clinical determination of prognosis, indicating their potential utility in current practice.