Enhancing the Detection of Dysmorphic Red Blood Cells and Renal Tubular Epithelial Cells with a Modified Urinalysis Protocol

Advances and Progress in Automated Urine Analyzers

The clinical analysis of urine has classically focused on conventional chemical-based urinalysis and urine microscopy. Contemporary advances in both analysis subsets have started to employ new technologies such as automated image analysis, flow cytometry, and mass spectrometry. In addition to new detection technologies, current analyzers have incorporated more advanced imaging, automated sample handing, and machine learning analyses into their workflow. The most advanced semiautomated analyzers can be interfaced with hospital medical record systems, and in the point-of-care setting, smartphones can be used for image analysis. This review will discuss current technological advancements in the field of urinalysis and urine microscopy.

Diagnostic Utility of Urine Microscopy in Kidney Diseases

Urine sediment analysis is a highly valuable yet underutilized test in today's advanced medical landscape. The analysis of urine sediment is a simple, cost-effective, and powerful diagnostic tool in the hands of a skilled nephrologist, generally in all kidney diseases and particularly more so in the setting of acute kidney injury (AKI). The impact of AKI is far-reaching and encompasses elevated mortality rates, increased morbidity, longer hospital stays, and higher overall healthcare expenses. Timely and compartmental diagnosis of AKI with the use of a simple urine sediment analysis leads to targeted therapeutic strategies and also serves as a prognostic guide. The widespread use of automated analysis in recent times has its own set of limitations, as it fails to identify pathological casts, crystals, and dysmorphic red blood cells (RBCs). Hence, it is the need of the hour to learn this time-honored art of urine sediment analysis, to provide comprehensive patient care.

Hand-Powered Point-of-Care: Centrifugal Microfluidic Platform for Urine Routine Examination (μCUREX)

Urinalysis is one of the simplest and most common medical tests in modern cities. With the assistance of professional technicians and equipment, people in metropolitan areas can effortlessly acquire information about their physiological conditions from traditional clinical laboratories. However, the threshold, including precise benchtop equipment and well-trained personnel, still remains a considerable dilemma for residents in healthcare-poor areas. Hence, it is a crucial and urgent topic to develop a smart and affordable widget to address this challenge. To improve the healthcare rights of residents, we proposed a disposable centrifugal microfluidic urine routine examination platform (named μCUREX) actuated with a modified hand-powered fan. Two parts of urinalysis (sediment test and chemical strip test) were integrated into the μCUREX disc. The influence on sedimentation by variant hand-powered manipulation was simulated using COMSOL. As a result, more than 70% of the sediment can be collected. Moreover, the color change of chemical strip papers (indicators for glucose, pH, protein, and occult blood) was recorded with a 3D-printed studio and analyzed after reaction with chemical-spiked and pH-adjusted artificial and human urine specimens. The whole process can be completed within 10 min, with only 200 μL of urine needed. In conclusion, we successfully constructed an ultra-low-cost point-of-care platform for urinalysis in extremely resource-poor settings. The handy size, high affordability, and user-friendliness of the μCUREX disc provide strong potential and feasibility in solving problems in resource-poor settings. Furthermore, we highly expect the μCUREX platform to improve the level of healthcare in resource-limited areas.

Urinary red blood cell-derived microparticles and phosphatidylserine-exposing red blood cells in glomerular and non-glomerular hematuria patients

BACKGROUND

Distinguishing glomerular hematuria (GH) from non-glomerular hematuria (NGH) is important for treating the cause of hematuria. We aimed to determine red blood cell-derived microparticles (RMPs) and phosphatidylserine (PS)-exposing red blood cells (RBCs) and evaluate their use for diagnosing GH and NGH patients.

METHODS

All patients received a physical assessment and urological examination. Dysmorphic RBCs (dRBCs) and acanthocytes were examined using a light microscope. The urinary RMPs and PS-exposing RBCs were determined using flow cytometry.

RESULTS

The ratio of RMPs to RBCs was higher in GH patients (n = 29) than in NGH patients (n = 29) (1.06 vs. 0.18). The value of the sum of the PS-exposing RBCs plus RMPs divided by the number of RBCs was higher in GH patients than in NGH patients (48.3% vs. 19.4%). The percentage of RBCs was higher in GH patients than in NGH patients (54.5% vs. 21.8%). Similarly, both the percentages of acanthocytes and of non-acanthocytes were higher in GH patients than in NGH patients (29% vs. 7.7% and 25.4% vs. 14.2%, respectively). The ROC-AUC of the number of PS-exposing RBCs plus RMPs divided by the number of RBCs was 0.9 (95% CI, 0.82-0.97), and the RMPs:RBCs ratio was 0.88 (95% CI, 0.79-0.98). The ROC-AUCs of the dRBCs and acanthocytes were 0.85 (95% CI, 0.78-0.95) and 0.88 (95% CI, 0.8-0.97), respectively.

CONCLUSIONS

Patients with GH have higher numbers of urinary RMPs and PS-exposing RBCs. These parameters have the potential to be predictive tools for classifying GH in the future.

Glomerular Hematuria and the Utility of Urine Microscopy: A Review

Evaluation of hematuria and microscopic examination of urine sediment are commonly used tools by nephrologists in their assessment of glomerular diseases. Certain morphological aspects of urine red blood cells (RBCs) seen by microscopy may help in identifying the source of hematuria as glomerular or not. Recognized signs of glomerular injury are RBC casts or dysmorphic RBCs, in particular acanthocytes (ring-shaped RBCs with protruding blebs). Despite being a highly operator-dependent test, urine sediment examination revealing these signs of glomerular hematuria has demonstrated specificities and positive predictive values ranging between 90%-100% for diagnosing glomerular disease, although sensitivity can be quite variable. Hematuria is a commonly used tool for diagnosing patients with proliferative glomerulonephritis such as IgA nephropathy, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, and lupus nephritis, sometimes even as a surrogate for kidney involvement. Studies examining the role for hematuria in monitoring and predicting adverse outcomes in these diseases have shown inconsistent results, possibly due to inconsistent definitions that often fail to consider specific markers of glomerular hematuria such as dysmorphic RBCs, acanthocytes, or RBC casts. A consensus definition of what constitutes glomerular hematuria would help standardize use in future studies and likely improve the diagnostic and prognostic value of hematuria as a marker of glomerulonephritis.

Evaluation of red blood cell parameters provided by the UF-5000 urine auto-analyzer in patients with glomerulonephritis

OBJECTIVES

The microscopic examination of hematuria, a cardinal symptom of glomerulonephritis (GN), is time-consuming and labor-intensive. As an alternative, the fully automated urine particle analyzer UF-5000 can interpret the morphological information of the glomerular red blood cells (RBCs) using parameters such as UF-5000 small RBCs (UF-%sRBCs) and Lysed-RBCs.

METHODS

Hematuria samples from 203 patients were analyzed using the UF-5000 and blood and urine chemistries to determine the cut-off values of RBC parameters for GN and non-glomerulonephritis (NGN) classification and confirm their sensitivity to the IgA nephropathy and non-IgA nephropathy groups.

RESULTS

The UF-%sRBCs and Lysed-RBCs values differed significantly between the GN and NGN groups. The cut-off value of UF-%sRBCs was >56.8% (area under the curve, 0.649; sensitivity, 94.1%; specificity, 38.1%; positive predictive value, 68.3%; and negative predictive value, 82.1%), while that for Lysed-RBC was >4.6/μL (area under the curve, 0.708; sensitivity, 82.4%; specificity, 56.0%; positive predictive value, 72.6%; and negative predictive value, 69.1%). Moreover, there was no significant difference in the sensitivity between the IgA nephropathy and non-IgA nephropathy groups (87.1 and 89.8% for UF-%sRBCs and 83.9 and 78.4% for Lysed-RBCs, respectively). In the NGN group, the cut-off values showed low sensitivity (56.0% for UF-%sRBCs and 44.0% for Lysed-RBCs).

CONCLUSIONS

The RBC parameters of the UF-5000, specifically UF-%sRBCs and Lysed-RBCs, showed good cut-off values for the diagnosis of GN.

A Microfluidic Detection System for Bladder Cancer Tumor Cells

The clinical characteristics of excreted tumor cells can be found in the urine of bladder cancer patients, meaning the identification of tumor cells in urine can assist in bladder cancer diagnosis. The presence of white blood cells and epithelial cells in the urine interferes with the recognition of tumor cells. In this paper, a technique for detecting cancer cells in urine based on microfluidics provides a novel approach to bladder cancer diagnosis. The bladder cancer cell line (T24) and MeT-5A were used as positive bladder tumor cells and non-tumor cells, respectively. The practicality of the tumor cell detection system based on microfluidic cell chip detection technology is discussed. The tumor cell (T24) concentration was around 1 × 10⁴ to 300 × 10⁴ cells/mL. When phosphate buffer saline (PBS) was the diluted solution, the tumor cell detected rate was 63–71% and the detection of tumor cell number stability (coefficient of variation, CV%) was 6.7–4.1%, while when urine was the diluted solution, the tumor cell detected rate was 64–72% and the detection of tumor cell number stability (CV%) was 6.3–3.9%. In addition, both PBS and urine are tumor cell dilution fluid solutions. The sample was analyzed at a speed of 750 microns per hour. Based on the above experiments, a system for detecting bladder cancer cells in urine by microfluidic analysis chip technology was reported. The rate of recognizing bladder cancer cells reached 68.4%, and the speed reached 2 mL/h.

Comparison of the diagnostic performance of two automated urine sediment analyzers with manual phase-contrast microscopy

Background

Recently, several manufacturers have launched automated urinalysis platforms. This study aimed to compare the diagnostic performance of the UF-5000 (Sysmex Corporation, Kobe, Japan) and the cobas® u 701 (Roche Diagnostics, Rotkreuz, Switzerland) urine sediment analyzers with manual phase-contrast microscopy as the reference method.

Methods

A total of 195 urine samples were analyzed on both automated platforms and subjected to manual microscopic examination. Agreement was assessed by Cohen’s kappa (κ) analysis. Sensitivities and specificities were calculated.

Results

The agreement of the UF-5000 with manual microscopy was almost perfect (κ > 0.8) for red (RBC) and white blood cells (WBC), renal tubular epithel cells, hyaline casts, bacteria (BACT) and yeast (YLC), substantial (κ = 0.61–0.80) for squamous epithel cells (SEC) and pathologic casts, and moderate (κ = 0.41–0.60) for transitional epithel cells. The cobas® u 701 showed substantial agreement (κ = 0.61–0.80) for WBC, moderate agreement (κ = 0.41–0.60) for hyaline casts, and fair agreement (κ = 0.21–0.40) for RBC, SEC, non-squamous epithel (NEC), pathologic casts, BACT and YLC. The UF-5000 sensitivities ranged between 98.5% for RBC and 83.3% for pathological casts. The cobas® u 701 showed sensitivities between 83.0% for WBC and 31.6% for YLC.

Conclusions

The UF-5000 (Sysmex) analyzer showed a better diagnostic agreement with manual phase-contrast microscopy compared to the cobas® u 701 (Roche) module. The Sysmex platform showed reliable results for urine sediment analysis. However, pathological samples should be verified with manual microscopy.

Urinary cylinders: what pediatrician and nephrologist need to know

Clinical urine test with the correct interpretation can help the clinician in the diagnosis of the urinary system diseases, as well as other organs and systems. Most laboratories in medical institutions are currently switching to an automated urinary sediment test, but microscopy appears relevant. Unfortunately, clinicians often interpret only three or four (most often proteinuria, leukocyturia and erythrocyturia) of all the numerous indicators of urine test, unfairly ignoring the others. The urinary cylinders are one of these important elements of the urinary sediment. The article presents the characteristics of the main types of urinary cylinders, their origin, composition, morphology and clinical significance.

Small Red Blood Cell Fraction on the UF-1000i Urine Analyzer as a Screening Tool to Detect Dysmorphic Red Blood Cells for Diagnosing Glomerulonephritis

Background

Dysmorphic red blood cells (dRBCs) are first-line biomarkers for detecting glomerulonephritis (GN) in patients with hematuria. The UF-1000i system (Sysmex, Kobe, Japan), based on flow cytometry, provides small red blood cell (RBC) values (UF-1000i [UF]-%sRBCs). We evaluated the clinical application of UF-%sRBCs for detecting %dRBCs and GN.

Methods

Urine samples of 103 patients (47 with GN; 56 without GN [NGN]) were analyzed using UF-1000i urinalysis, phase-contrast microscopy (PCM), and urine chemistry. Serum creatinine (mg/dL), serum albumin (g/dL), serum protein (mg/dL), urine protein (mg/dL), and urea nitrogen (mg/dL) levels were measured using an automated chemical analyzer. To determine the cut-off level of predicting GN, ROC curve was analyzed.

Results

UF-%sRBCs, %dRBCs, urine protein, serum creatinine, and estimated-glomerular filtration rate differed between the GN and NGN groups, with the greatest differences detected for UF-%sRBCs and %dRBCs (P<0.0001). In ROC curve analysis, urine protein had the highest area under the curve (0.828), followed by %dRBCs (0.771) and UF-%sRBCs (0.745). To screen for GN, the best cut-off values of UF-%sRBCs and %dRBCs were >40.5% and >6.7%, respectively. %dRBCs (P=0.0001) and UF-%sRBCs (P=0.0006) differed between the GN and NGN groups in patients with isolated hematuria but without proteinuria.

Conclusions

UF-%sRBCs had similar diagnostic power to %dRBCs determined by PCM for identifying patients with GN. UF-%sRBCs may be more useful for diagnosing GN in patients with isolated hematuria. Predicting %dRBCs using UF-1000i will provide information on possible GN in patients presenting with asymptomatic hematuria.

High false positive rate of white blood cells in urine samples of pregnant women may be caused by epithelial cells being misclassified by the sysmex UF-1000i urine flow cytometer

Background

The UF‐1000i has been widely used in screening urinary sediments. However, the interference factor of the UF‐1000i in the screening urinary sediments of pregnant women has not been reported. The aim of the study was to demonstrate that epithelial cells (ECs) cause a high false positive rate of white blood cells (WBCs) by the UF‐1000i in pregnant women.

Methods

Urine samples were collected from 207 pregnant women. All samples were measured by the UF‐1000i and a microscopic method.

Results

The areas under the curve (AUC) for WBC and EC counts were 0.837 (95% CI, 0.773–0.901) and 0.844 (95% CI, 0.785–0.903), respectively. The positive rates of the WBC and EC were 73.43% and 37.20%, respectively, by the UF‐1000i, and they were 19.32% and 72.95% by the microscopic method. The positive predictive value, negative predictive value, false positive rates, and false negative rates by the UF‐1000i were for WBC 25.66%, 98.18%, 74.34%, and 1.82%, respectively, and for EC they were 96.1%, 40.77%, 3.9%, and 59.23%, respectively. The coefficient of correlation R value was 0.503 (P < 0.01) between WBC by UF‐1000i and EC by the microscopic method in WBC false positive samples.

Conclusions

EC could be an interference factor for the UF‐1000i in screening urinary WBC of pregnant women, and the high false positive rate for WBC may be caused by ECs being misclassified as WBCs by the UF‐1000i. © 2018 The Authors. Cytometry Part B: Clinical Cytometry published by Wiley Periodicals, Inc. on behalf of International Clinical Cytometry Society.