Indications and results of renal biopsy in children: a 36-year experience

Comparative analysis of ultrasound-guided percutaneous biopsy of native kidneys in children and adults using the free-flank supine antero-lateral decubitus positioning

PURPOSE

Ultrasound-guided percutaneous biopsy (USPB) of the native kidneys is the preferred diagnostic method for several nephrological conditions in both adult and pediatric populations. Conventionally, native kidney biopsies are conducted with patients in the prone position (PP). However, an alternative approach involving the supine oblique antero-lateral position (SALP) has been explored, particularly for individuals who are obese, elderly, or critically ill.

METHODS

This study aimed to assess the feasibility and outcomes of USPB performed in SALP with a Free-Flank setting (FF-SALP) in pediatric patients (Group A) compared to adults (Group B). Data from kidney biopsies conducted between 2008 and 2021 were gathered. The study focused on the safety and the prevalence of biopsy samples containing a minimum of 10 glomeruli, histopathological yield in both groups.

RESULTS

Complication rates were low in both groups (5.6% vs. 3.7%; p = 0.454), without major complications noted. The pediatric group achieved a significantly higher mean number of glomeruli per biopsy compared to the adult group (20.6 ± 12.3 vs. 15.7 ± 9.4; p < 0.001). However, when evaluating the minimum threshold of 10 glomeruli (76.3% vs. 68.5%; p = 0.072) and histopathologic yield (95.3% vs. 93.5%; p = 0.408), no differences were observed between groups.

CONCLUSION

USPB of native kidneys in the FF-SALP position is a safe and effective method for tissue sampling in patients with parenchymal disease. It demonstrated comparable diagnostic yields and complication rates in the pediatric and adult populations, providing advantages in terms of airway management, making it particularly useful for pediatric patients that require general anesthesia.

Percutaneous kidney biopsies in children: a 24-year review in a tertiary center in northern Portugal

INTRODUCTION

Percutaneous kidney biopsy (KB) is crucial to the diagnosis and management of several renal pathologies. National data on native KB in pediatric patients are scarce. We aimed to review the demographic and clinical characteristics and histopathological patterns in children who underwent native percutaneous KB over 24 years.

METHODS

Retrospective observational study of patients undergoing native percutaneous KB in a pediatric nephrology unit between 1998 and 2021, comparing 3 periods: period 1 (1998-2005), period 2 (2006-2013), and period 3 (2014-2021).

RESULTS

We found that 228 KB were performed, 78 (34.2%) in period 1, 91 (39.9%) in period 2, and 59 (25.9%) in period 3. The median age at KB was 11 (7-14) years. The main indications for KB were nephrotic syndrome (NS) (42.9%), hematuria and/or non-nephrotic proteinuria (35.5%), and acute kidney injury (13.2%). Primary glomerulopathies were more frequent (67.1%), particularly minimal change disease (MCD) (25.4%), IgA nephropathy (12.7%), and mesangioproliferative glomerulonephritis (GN) (8.8%). Of the secondary glomerulopathies, lupus nephritis (LN) was the most prevalent (11.8%). In group 1, hematuria and/or non-nephrotic proteinuria were the main reasons for KB, as opposed to NS in groups 2 and 3 (p < 0.01). LN showed an increasing trend (period 1-3: 2.6%-5.3%) and focal segmental glomerular sclerosis (FSGS) showed a slight decreasing trend (period 1-3: 3.1%-1.8%), without statistical significance.

CONCLUSIONS

The main indication for KB was NS, which increased over time, justifying the finding of MCD as main histological diagnosis. LN showed an increase in incidence over time, while FSGS cases did not increase.

Risk Factors for Urinary Tract Infections in Children with Hematuria in the Emergency Department

INTRODUCTION

Hematuria is a worrisome symptom in children and is sometimes associated with urinary tract infections (UTIs). This study aimed to identify useful clinical factors that can predict UTIs in hematuria patients without pyuria in the pediatric emergency department (ED).

METHODS

We retrospectively recruited patients with hematuria from the pediatric ED. Clinical symptoms, urine biochemistry and microscopic examination results, and blood laboratory tests were analyzed to identify the predictors of UTIs. Patients were divided into the verbal group (age ≥ 2 years) and non-verbal group (age < 2 years) for identifying predictors of UTIs. Causes of hematuria were also investigated.

RESULTS

A total of 161 patients with hematuria without pyuria were evaluated. Among symptoms, dysuria was significantly correlated with UTIs. Regarding urine biochemistry data, urine esterase and urine protein > 30 mg/dl were found to be significant parameters for predicting UTIs, while urine esterase and urine nitrite showed significant differences in children with age < 2 years. In the urine microscopic examinations, urine red blood cells (RBC) > 373/µL in children aged ≥ 2 years and urine RBC > 8/µL in children aged < 2 years were associated with UTIs. In addition, UTIs and urinary tract stones were found to be the top two causes of hematuria.

CONCLUSIONS

Dysuria, urine esterase, urine nitrite, and urine protein may be useful parameters for predicting UTIs in pediatric patients with hematuria but no pyuria in the ED. In addition, a UTI was the most commonly identified etiology of hematuria without pyuria, followed by urinary tract stones.

Role of detached podocytes in differentiating between minimal change disease and early focal segmental glomerulosclerosis, can we rely on routine light microscopy?

BACKGROUND

Detachment of podocytes represents a turning point in the development of glomerular sclerosis and consequently, of CKD progression. Furthermore, detachment may differentiate minimal change disease (MCD) cases-which have only podocyte effacement-from early focal segmental glomerulosclerosis (FSGS) in which effacement and detachment are observed by electron microscopy. Noteworthy, it is not uncommon for early FSGS to present with clinical presentation and light microscopy (LM) pictures identical to MCD. In our routine practice, we often find cells that lie freely in Bowman's space by LM. In this study, we try to determine whether these cells are detached podocytes that are worth reporting or just an artifact that can be ignored.

METHODS

To the best of our knowledge, no study has discussed the accuracy of LM in detecting detached podocytes by the routinely used stains. We retrospectively selected 118 cases that were diagnosed as MCD by LM, and searched for detached cells in Bowman's space in their archived, routinely stained LM slides. After that, we tried to find any correlation between the clinical course, detached cells in LM picture and the EM reports.

RESULTS

LM can significantly detect detached podocytes with a positive predictive value of 93%, specificity of 85%, and sensitivity of 46%. Significant correlations were found between detached cells and degree of proteinuria and late steroid resistance.

CONCLUSION

Detecting detached podocytes by LM is a specific finding that must be reported whenever detected, as it predicts response to steroids and may be able to differentiate MCD from early FSGS by identifying patients who could have podocytopenia.

Epidemiology of biopsy-proven glomerular diseases in Chinese children: A scoping review

Background

Glomerular disease is the leading cause of chronic kidney disease globally. No scoping review reports have focused on China's spectrum of glomerular diseases in children. This study aimed to systematically identify and describe retrospective studies on pediatric glomerular disease based on available data on sex, age, study period, and region.

Methods

Six databases were systematically searched for relevant studies from initiation to December 2021 in PubMed, Embase, Web of Science, Global Health Library, Wangfang Database, and CNKI.

Results

Thirty-four studies were identified in the scoping review, including 40,430 patients with biopsy-proven diagnoses. The proportion of boys was significantly higher than that of girls. In this study, 28,280 (70%) cases were primary glomerular disease, 10,547 (26.1%) cases were diagnosed as secondary glomerular disease, and 1146 (2.8%) cases were hereditary glomerular disease. Minimal change disease is the most common glomerular disease among children in China, followed by mesangial proliferative glomerulonephritis, IgA nephropathy, and purpura nephritis. We observed increments in glomerular diseases in periods 2 (2001-2010) and 3 (2011-2021). The proportion of major glomerular diseases varies significantly in the different regions of China.

Conclusion

The spectrum of pediatric glomerular diseases varied across sex, age groups, study periods, and regions, and has changed considerably over the past 30 years.

Clinical and histopathological study of renal biopsy in Nepalese children: A single center experience

BACKGROUND

Glomerular diseases are important causes of morbidity and mortality among children in developing countries. Renal biopsy is the gold standard for determining histological diagnosis, prognosis, and therapy options. This study aimed to investigate the clinical, histopathological, and direct immunofluorescence findings of renal biopsy results in Nepalese children under 18 years old.

METHODS

In this retrospective cross-sectional study, the available data from children who had undergone kidney biopsy between 2016 and the end of 2020 were evaluated. Demographic data, indications of biopsy, histopathologic findings, and direct immunofluorescence findings were collected and presented.

RESULTS

The mean age of the patients was 12.14 ± 4.07 years. Male/female ratio was 1:1. The majority of biopsy cases were aged between 11-15 years of age. The most common indication for biopsy in children was nephrotic syndrome (68.25%). Lupus nephritis with 28 cases (22.22%) had the highest frequency in overall renal biopsies. Minimal change disease (MCD) with 22 cases (17.46%) followed by Ig A nephropathy with 16 cases (12.69%) were the most frequent primary glomerulonephritis. Lupus nephritis showed full house positivity, and MCD showed full house negativity in all Direct immunofluorescence (DIF) parameters, whereas immunoglobulin A nephropathy showed 100% positivity in Ig A in DIF.

CONCLUSIONS

Nephrotic syndrome was the most common indication for renal biopsy. The most common primary glomerulonephritis was MCD, while secondary glomerulonephritis was lupus nephritis. Clinical data, light microscopy, and direct DIF played an integral role in the overall final diagnosis.

Metabolic Fingerprinting of Fabry Disease: Diagnostic and Prognostic Aspects

Fabry disease (FD) is an X-linked lysosomal disease due to a deficiency in the activity of the lysosomal-galactosidase A (GalA), a key enzyme in the glycosphingolipid degradation pathway. FD is a complex disease with a poor genotype–phenotype correlation. In the early stages, FD could involve the peripheral nervous system (acroparesthesias and dysautonomia) and the ski (angiokeratoma), but later kidney, heart or central nervous system impairment may significantly decrease life expectancy. The advent of omics technologies offers the possibility of a global, integrated and systemic approach well-suited for the exploration of this complex disease. In this narrative review, we will focus on the main metabolomic studies, which have underscored the importance of detecting biomarkers for a diagnostic and prognostic purpose in FD. These investigations are potentially useful to explain the wide clinical, biochemical and molecular heterogeneity found in FD patients. Moreover, the quantitative mass spectrometry methods developed to evaluate concentrations of these biomarkers in urine and plasma will be described. Finally, the complex metabolic biomarker profile depicted in FD patients will be reported, which varies according to gender, types of mutations, and therapeutic treatment.

Overview of pediatric kidney transplantation

Kidney transplantation is the treatment of choice for pediatric patients with end-stage kidney disease. Unlike adult recipients undergoing transplantation, special considerations must be taken when transplanting children based on the underlying etiology of kidney disease, previous surgical procedures, anatomical limitations and necessary technical adjustments. Additionally, the choice of donor must be measured to ensure optimal graft survival given a longer post-transplant life expectancy. Those topics as well as frequently encountered postoperative complications are also discussed in this publication.

Therapeutic Approach for Recurrent Focal Segmental Glomerulosclerosis in Pediatric Renal Transplant Recipients: A Single-Center Experience

<b><i>Introduction:</i></b> Recurrence of focal segmental glomerulosclerosis (FSGS) after kidney transplantation (KTx) develops in 40% of patients, leading to graft loss in half of cases. Extracorporeal apheretic treatments, combined with immunosuppressive drugs, seem to be the most promising therapies, but at now limited reports are available, mainly in pediatric patients. <b><i>Objective:</i></b> We aimed to assess the efficacy of immunoadsorption (IA) to treat recurrent FSGS in pediatric patients. <b><i>Methods:</i></b> We report a case series of 4 pediatric patients (aged 4–12 years) followed at our institution for early recurrent FSGS after KTx. FSGS recurrence was treated with early and intensive apheretic treatments IA. <b><i>Results:</i></b> After IA initiation, a partial remission (PR) of proteinuria at 24-month follow-up was achieved only in 1 patient. The others showed a mild reduction of nephrotic proteinuria, without PR, but gained a significant improvement in clinical signs of nephrotic syndrome (reduction of edema, increased serum albumin, and total protein levels). After a median follow-up of 38 (22–48) months, renal function was almost stable over time in all patients, except one who returned to hemodialysis after 22 months. No severe IA-related complications occurred. <b><i>Conclusions:</i></b> According to our clinical experience, IA revealed as a safe and effective therapy to treat patients with recurrent FSGS after KTx and it could maintain stable renal function in 75% of patients.

Clinical outcomes in pediatric patients with normal renal histopathology

Background

There have been some cases where abnormal histopathologic findings could not be found in the kidney could even with proper specimen collection through percutaneous renal biopsy (PRB) in accordance with its indication. We analyzed the incidence and clinical outcomes of children who showed normal histopathological findings in their PRBs.

Methods

The medical records of 552 pediatric subjects who underwent PRB between 2005 and 2016 were reviewed. Twenty-six subjects were excluded because allograft biopsy was performed in nine subjects, and the age at biopsy was greater than 18 years in 17 subjects. Finally, 526 subjects were enrolled in this study.

Results

Of the 526 pediatric patients, 32 (6.1%) showed no histopathological abnormalities in their PRBs. The male-to-female ratio of the patients was 1.9:1, and the mean ages at the first visit and at biopsy were 10.6 ± 4.1 and 11.4 ± 3.8 years, respectively. In accordance with the biopsy indications, recurrent gross hematuria showed the highest incidence rate, but combined hematuria and proteinuria had the lowest incidence rate regarding normal renal histopathology among all the subjects. At a mean follow-up of 35.5 ± 23.6 months, urinary abnormalities had improved in more than 50% of the subjects with normal renal histopathology, and none of the patients showed progression to end-stage renal disease or required rebiopsy due to symptom worsening during the follow-up period.

Conclusion

The clinical outcomes of children with normal PRB histopathologic findings are generally good. Further studies to evaluate their long-term outcomes are needed.

Renal Biopsy in Children-Effect on Treatment Decisions: A Single-Center Experience

Renal biopsy is an important diagnostic tool, though invasive and carries risks involved with sedation. The authors wanted to compare suspect histopathological diagnosis with final diagnosis and find out impact of biopsy findings on treatment. They retrospectively analyzed 108 patients. Details of patients, diagnosis, treatment and complications due to kidney biopsy were documented. Statistical analysis was done using SPSS version 20.0 (IBM, NY). Indications of 108 children (69 boys, 39 girls) undergoing renal biopsy were steroid-resistant nephrotic syndrome (35.1%), steroid-dependent nephrotic syndrome requiring calcineurin inhibitors (CNI) (12%), nephrotic range proteinuria with atypical features (16.7%), lupus nephritis (13%), and acute kidney injury (AKI) stage 3 (17.6%). Suspect and histopathological diagnoses were similar in 53% cases with agreement factor of 0.462. Treatment changed in 28.7%. Renal biopsy made substantial impact in patients with nephrotic range proteinuria with atypical features (55.6%) and AKI stage 3 (52.6%). One (0.9%) had developed gross hematuria, which resolved spontaneously.

Role of Complement in Regulating Inflammation Processes in Renal and Prostate Cancers

For decades, the complement system, the central pillar of innate immune response, was recognized as a protective mechanism against cancer cells and the manipulation of complement effector functions in cancer setting offered a great opportunity to improve monoclonal antibody-based cancer immunotherapies. Similarly, cellular senescence, the process of cell cycle arrest that allow DNA and tissue repair has been traditionally thought to be able to suppress tumor progression. However, in recent years, extensive research has identified the complement system and cellular senescence as two main inducers of tumour growth in the context of chronic, persistent inflammation named inflammaging. Here, we discuss the data describing the ambivalent role of senescence in cancer with a particular focus on tumors that are strongly dependent on complement activation and can be understood by a new, senescence-related point of view: prostate cancer and renal cell carcinoma.

Peripheral nervous system manifestations of Shiga toxin-producing E. coli-induced haemolytic uremic syndrome in children

Background

The Neurological involvement is the most common extra-renal complication of Shiga toxin-producing E. coli-hemolytic uremic syndrome (HUS) or typical HUS. On brain magnetic resonance examination, main neurological signs encompass acute lesions of the basal ganglia and the white matter, which could usually regress after Eculizumab infusion. In contrast, peripheral nervous system (PNS) manifestations in typical HUS are very rare and, when occurring, they require a careful management of neurological sequelae and an intensive multidisciplinary neuro-rehabilitation program.

Case presentation

Here, we present two pediatric cases of severe and complicated typical HUS with PNS manifestations who required therapeutic treatment and an intensive multidisciplinary neuro-rehabilitation program.

In both cases, PNS manifestations were followed by the recovery from typical HUS-related severe central neurological damage and manifested mainly with marked bilateral motor deficit and hyporeflexia/areflexia in the lower limbs. The peripheral polyneuropathy was treated with immunosuppressive therapy (methylprednisolone boluses, i.v. immunoglobulins, plasma exchange), followed by a prolonged intensive neuro-rehabilitation program. After 8 months of rehabilitation, both patients gained complete functional recovery.

Conclusions

PNS manifestations during typical HUS are a rare event and potentially leading to severe disability. A timely clinical assessment is mandatory to set up a prompt therapeutic and rehabilitation program and to obtain a complete clinical and functional recovery.

[Efficacy and safety of steroid combined with immunosuppressants in the treatment of primary IgA nephropathy in children: a Meta analysis]

OBJECTIVE

To systematically evaluate the efficacy and safety of steroid combined with immunosuppressants in the treatment of primary IgA nephropathy in children.

METHODS

English and Chinese electronic databases were searched to include the studies on the efficacy and safety of steroid combined with immunosuppressants versus steroid alone in the treatment of primary IgA nephropathy in children. Outcome measures included proteinuria remission rate, urinary protein quantification, incidence of adverse events, estimated glomerular filtration rate, and incidence of renal dysfunction. Review Manager 5.3 software was used for data analysis.

RESULTS

A total of 7 studies with 381 children were included. The children had moderate to severe proteinuria. The Meta analysis showed that compared with the steroid alone group, the steroid combined with immunosuppressants group achieved a significantly higher rate of proteinuria remission (RR=1.36, 95%CI: 1.19-1.55, P<0.001) and significantly lower urinary protein quantification (SMD=-0.82, 95%CI: -1.23 to -0.41, P<0.001). There was no significant difference in the incidence rate of adverse events between the two groups (RR=1.28, 95%CI: 0.92-1.77, P=0.14).

CONCLUSIONS

The current evidence shows that for children with primary IgA nephropathy who have moderate to severe proteinuria, steroid combined with immunosuppressants has a better effect than steroid alone and does not increase the incidence rate of adverse events.

Low C3 Serum Levels Predict Severe Forms of STEC-HUS With Neurologic Involvement

Background: The correlation between the severity of hemolytic uremic syndrome related to Shiga toxin–producing Escherichia coli (STEC-HUS) and involvement of the complement system has been examined in a small number of studies, with conflicting results. In the present study, we investigated whether serum C3 levels on admission are associated with neurologic involvement.

Methods: To this purpose, 68 consecutive STEC-HUS patients were recruited and main clinical and laboratory variables ad hospital admission were compared between those with or without neurologic involvement.

Results: STEC-HUS patients who developed neurologic involvement (NI) showed significant higher leukocyte count, C-reactive protein and hemoglobin, and lower sodium levels as compared with those without. Interestingly, baseline serum levels of C3 were significantly lower in patients with NI as compared with those without (p < 0.001). Moreover, when stratified according to need of Eculizumab rescue therapy due to severe NI, patients treated with this drug showed baseline C3 serum levels significantly lower than those who were not (p < 0.001).

Low C3 was independent risk factor for NI in our patients' population when entered as covariate in a multivariate logistic regression analysis including other major variables previously proposed as possible predictors of poor prognosis in STEC-HUS (for instance, leukocyte count, c-reactive protein, sodium levels) (HR 6.401, 95%CI 1.617–25.334, p = 0.008 for C3).

To underline the role of complement in the worsening of STEC-HUS patients' clinical conditions and outcomes, all patients were divided into two groups according to the baseline lower vs. normal serum levels of C3 and the main data on care needs were assessed. Interestingly more patients with lower C3 serum levels required renal replacement therapy (p = 0.024), anti-hypertensive therapy (p = 0.011), Intensive Care Unit admission (p = 0.009), and longer hospitalization (p = 0.003), thus displaying significantly more severe disease features as compared with those with normal C3 serum levels.

Conclusions: Our data suggests that children with STEC-HUS with decreased C3 concentrations at admission are more likely to develop neurologic involvement and are at increased risk of having severe clinical complications.

Steroid therapy in children with IgA nephropathy

IgA nephropathy (IgAN) is one the most common primary glomerulonephritis in children and adolescents worldwide, with 20% of children developing end-stage kidney disease (ESKD) within 20 years of diagnosis. There is a need for treatment guidelines, especially for steroids in children with primary IgAN, since the STOP-IgA trial casts doubts on the use of steroids in adults with intermediate risk. Pediatricians are prone to prescribe steroids in addition to renin-angiotensin system blockade (RASB) when proteinuria is > 0.5 g/l, eGFR deteriorates < 70 ml/min/1.73 m², or when a biopsy sample shows glomerular inflammation. Lack of randomized controlled trials (RCTs) in children with IgAN has led to an absence of consensus on the use of immunosuppressive agents in the treatment of progressive IgAN. This literature review evaluates the available evidence on steroid treatment in children with IgAN.

Risk factors for complications of percutaneous ultrasound-guided renal biopsy in children

BACKGROUND

Percutaneous ultrasound-guided renal biopsy (PURB) is an invasive but essential procedure in establishing the histologic diagnosis of pediatric renal diseases. Large studies which describe PURB complications and its contributory risk factors are scarce in the pediatric literature.

METHODS

Patients who underwent real-time PURB from September 2011 to August 2017 were retrospectively reviewed. Data pertaining to clinical characteristics, histologic diagnosis and biopsy-related complications were collected. In addition, the risk factors for complications were also analyzed.

RESULTS

Overall, 183 patients (109 females) were enrolled and 201 biopsies were obtained. The mean age was 14.4 ± 13.7 years. Over 98% of the biopsies were considered adequate in quality. The major complications were perirenal hematoma requiring blood transfusion (4 cases, 2.0%), followed by perirenal abscess (1 case, 0.5%) and arteriovenous fistula (1 case, 0.5%). All patients recovered without sequelae after treatment. Hypertension, low estimated glomerular filtration rate (eGFR) and anemia were more common in patients with complication than in those without. Further logistic regression model analysis demonstrated that eGFR <30 ml/1.73m²/min was an independent risk factor for major complications.

CONCLUSIONS

Perirenal hematoma needing blood transfusion is the most common major complication for children undergoing renal biopsy. Low eGFR is an independent risk factor for major complications. Early recognition and timely treatment should be delivered to children with renal function impairment accordingly.

Planificación de un modelo integral de cuidados en una adolescente sometida a biopsia renal

Descripción caso: adolescente de 14 años que presentaba hematuria y proteinuria aisladas desde hace apenas un año, en tratamiento farmacológico. Candidata para ser sometida a la técnica, ingresa en la unidad de nefrología pediátrica. En la valoración inicial, se detectó un posible caso de trastorno de la conducta alimentaria (TCA), puesto en conocimiento del equipo de salud. Descripción del plan de cuidados: Se llevó a cabo un plan de cuidados integral que se centraba tanto en los aspectos físicos como psicosociales del individuo. En cuanto a los diagnósticos seleccionados, previo a la biopsia primó el temor y, tras ella, el deterioro de la integridad tisular y de estos a su vez derivaron los de disposición para mejorar los conocimientos, disposición para mejorar el afrontamiento, riesgo de sangrado, riesgo de infección, retención urinaria y dolor agudo. Evaluación del plan: La paciente estuvo hospitalizada durante 48 horas, ya que después de la prueba presentó globo vesical. Durante su ingreso, quiso manejar su régimen terapéutico y conocer medidas para controlar el estrés ante la punción. Fue dada de alta con los problemas físicos resueltos y motivada para seguir aprendiendo sobre su proceso de enfermedad. Conclusiones: A la vista de nuestros resultados podemos concluir que el plan de cuidados aplicado a esta paciente adolescente fue efectivo respecto a todos los resultados esperados (NOC).

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.