The clinical art and science of urine microscopy

Establishing an External Quality Assessment (EQA) Program for Urinalysis in Medical Laboratories of Thailand

Thailand Association of Clinical Biochemists (TACB) introduced External Quality Assurance schemes (EQAs) for urinalysis (UA) using urine strips in medical laboratories of Thailand. The few available External Quality Assessment (EQA) programs on urinary microalbumin rarely include an evaluation of clinical cases. The aim of the present study was to assess a descriptive analysis of biochemical urinalysis including urine microalbumin in the Thailand laboratory practice. From January 2021 to December 2021, four surveys were organized. EQA urine samples were distributed to the participants by mail. The participants measured the UA of 2 samples quarterly and returned the results together with the information about their instruments and suggestion for the performance of the laboratory report quarterly. Moreover, summary of the situation of each laboratory performance was feedbacked by online system. Fifty-eight laboratories participated in the survey. The EQA panels included positive and negative samples. The analytical results for passed parameters of urine chemical test range from 79.3-100%. All special tests; microalbumin, creatinine, and beta-HCG showed correct result from 85.1-96.1%. The overall accuracy, specificity, and sensitivity were 92.6, 85.7, and 75,4%, respectively. The major issues were observed: the low sensitivity for the detection of low-concentration samples and the incapacity of several methods to detect the positive sample. The assessment is needed to continuously evaluate the improvement proficiency of laboratories in Thailand.

Leukocyturia and hematuria enable non-invasive differentiation of Bowman's capsule rupture severity in PR3-ANCA glomerulonephritis

BACKGROUND

Renal involvement is a common and severe complication of anti-neutrophil cytoplasmic antibody-(ANCA)-associated vasculitis potentially resulting in pauci-immune necrotizing and crescentic ANCA glomerulonephritis (GN) with rapid deterioration of kidney function, progression to end stage kidney disease or, if left untreated, lethal exitus. Analysis of the urinary sediment routinely supports clinical management of ANCA GN, but histopathological implications of aberrancies in the urinary sediment mostly remain elusive. Therefore, we aimed to systematically assess the correlation of aberrancies in the urinary sediment and clinico-pathologic findings.

METHODS

A total of 42 kidney biopsies with ANCA GN were retrospectively analyzed in a single-center observational study. Laboratory and histopathological parameters were systematically analyzed and correlated with findings of the urinary sediment.

RESULTS

In the overall ANCA GN cohort, leukocyturia and hematuria were associated among each other, and with markers for non-selective glomerular damage, respectively. Non-invasive measurement of leukocyturia indicated focal (but not extensive) Bowman's capsule rupture (BCR) specifically in proteinase-3 (PR3)-ANCA GN, whereas hematuria correlated with extensive (but not focal) BCR. Concerning intrarenal immune cell infiltration, leukocyturia was associated with tubulointerstitial plasma cell infiltration in PR3-ANCA GN. Finally, none of these associations were detectable in myeloperoxidase-ANCA GN, implying different modes of kidney damage.

CONCLUSION

We herein expand our current knowledge by providing evidence that leukocyturia and hematuria enable non-invasive differentiation of BCR severity specifically in PR3-ANCA GN.

Qualitative and quantitative proteomic and metaproteomic analyses of healthy human urine sediment

PURPOSE

The healthy human urine sediment proteome and metaproteome are investigated, to shed light on the variations of urine sediment proteins and metaproteins associated with sex and age.

EXPERIMENTAL DESIGN

Urine sediment samples are collected from 19 healthy subjects. Protein identification and quantification are performed by liquid chromatography coupled high-resolution mass spectrometry.

RESULTS

A total of 2736 human proteins were identified, which were primarily associated with inflammatory response and energy metabolism. For the metaproteome, 65 genera were identified that were primarily involved in translation and carbohydrate metabolic processes. The median biological coefficient variation of the proteome/metaproteome of human urine sediment was 0.5/0.72, similar to the proteome of human urine supernatant. In addition, sex and age were observed to affect the proteome and metaproteome of healthy human urine sediment.

CONCLUSION AND CLINICAL RELEVANCE

The healthy human urine sediment were characterized, indicating that urine sediment might represent an alternative resource for disease research in addition to urine supernatant, but the influence of sex and age must be considered in the study design process.

The polysaccharide chitosan facilitates the isolation of small extracellular vesicles from multiple biofluids

Several studies have demonstrated the potential uses of extracellular vesicles (EVs) for liquid biopsy-based diagnostic tests and therapeutic applications; however, clinical use of EVs presents a challenge as many currently-available EV isolation methods have limitations related to efficiency, purity, and complexity of the methods. Moreover, many EV isolation methods do not perform efficiently in all biofluids due to their differential physicochemical properties. Thus, there continues to be a need for novel EV isolation methods that are simple, robust, non-toxic, and/or clinically-amenable. Here we demonstrate a rapid and efficient method for small extracellular vesicle (sEV) isolation that uses chitosan, a linear cationic polyelectrolyte polysaccharide that exhibits biocompatibility, non-immunogenicity, biodegradability, and low toxicity. Chitosan-precipitated material was characterized using Western blotting, nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and relevant proteomic-based gene ontology analyses. We find that chitosan facilitates the isolation of sEVs from multiple biofluids, including cell culture-conditioned media, human urine, plasma and saliva. Overall, our data support the potential for chitosan to isolate a population of sEVs from a variety of biofluids and may have the potential to be a clinically amenable sEV isolation method.

Diagnostic Utility of Serial Microscopic Examination of the Urinary Sediment in Acute Kidney Injury

Background

Microscopic examination of the urinary sediment (MicrExUrSed) is an established diagnostic tool for AKI. However, single inspection of a urine specimen during AKI is a mere snapshot affected by timing. We hypothesized that longitudinal MicrExUrSed provides information otherwise not identified in a single inspection.

Methods

MicrExUrSed was undertaken in patients with AKI stage ≥2 and suspected intrinsic cause of AKI seen for nephrology consultation over a 2-year period. MicrExUrSed was performed on the day of consultation and repeated at a second (2-3 days later) and/or third (4-10 days later) interval. Cast scores were assigned to each specimen. Chawla scores (CS) 3-4 and Perazella scores (PS) 2-4 were categorized as consistent with acute tubular injury (ATI), whereas CS 1-2 and PS 0-1 were categorized as nondiagnostic for ATI (non-ATI). Nonrecovering AKI was defined as a rise in serum creatinine (sCr) ≥0.1 mg/dl between microscopy intervals.

Results

At least two consecutive MicrExUrSed were performed in 121 patients (46% women, mean age 61±14, mean sCr at consult of 3.3±1.9 mg/dl). On day 1, a CS and PS consistent with non-ATI was assigned to 64 (53%) and 70 (58%) patients, respectively. After a subsequent MicrExUrSed, CS and PS changed to ATI in 14 (22%) and 16 (23%) patients. Thus, 20%-24% of patients only revealed evidence of ATI after serial MicrExUrSed was performed. Patients with nonrecovering AKI were more likely to change their PS to the ATI category (odds ratio, 5.8; 95% CI, 1.7 to 19.3; P=0.005 and positive likelihood ratio, 2.0; 95% CI, 1.3 to 2.9).

Conclusions

Serial MicrExUrSed revealed diagnostic findings of ATI otherwise not identified in a single examination. A repeat MicrExUrSed may be warranted in patients AKI of unclear etiology that are not recovering.

The Italian External Quality Assessment (EQA) program on urinary sediment by microscopy examination: a 20 years journey

OBJECTIVES

In spite of the introduction of automated systems for urinary sediment analysis, microscopy examination remains the gold standard, and it is more than ever important to perform it with a good and reliable quality. External Quality Assessment (EQA) programs on urinary sediment are rare. The present paper provides an analysis of results from 2001 to date of the EQA Italian program which involves today 230 laboratories.

METHODS

The program includes four surveys per year. Participants are asked the identification and clinical associations of urinary sediment particles, shown as phase contrast microscopy images in the website of the Center of Biomedical Research (CRB) (2 surveys), and the diagnosis of clinical cases presented by both images and a short clinical history (2 surveys). The results of each survey are then scored and commented. In 20 years, 298 images were presented: 90 cells (9 types), 23 lipids (5 types), 87 casts (21 types), 53 crystals (14 types), 22 microorganisms (5 types), and 23 contaminants (9 types). Moreover, 27 clinical cases, covering a wide spectrum of conditions with different degrees of complexity, were presented to participants.

RESULTS

Identification: among urinary particle categories, the correct identification rate (obtained for each particle from the sum of correct + partially correct answers) was very high for micro-organisms (mean ± SD: 96.2 ± 3.5%), high for lipids (88.0 ± 11.8%) and crystals (87.0 ± 16.5%) followed, in decreasing order, by cells (82.1 ± 15.9%), casts (81.8 ± 14.8%), and contaminants (76.7 ± 22.1%). Clinical associations (n=67): the rate of correct answers was 93.5 ± 5.7% ranging from 75.0 to 100% for all but one clinical association (i.e., acute glomerulonephritis: 55.4%). Clinical cases: throughout surveys, due to the overall rate of particle misidentification, only 59.8 ± 17.1%, (range 32.5-88.7%) of participants achieved access to clinical diagnosis. Of these, 88.7 ± 10.6% (range 59.9-99.3%) were able to indicate the correct diagnosis.

CONCLUSIONS

Our program can be used as a tool to improve the identification of urine particles and the knowledge of their clinical meaning and to encourage specialists of laboratory medicine to correlate urinary findings with other laboratory data and the clinical history, an aspect that improves the value of the day by day work.

Expanding the Role for Kidney Biopsies in Acute Kidney Injury

Acute kidney injury (AKI) is a highly heterogeneous, common, and potentially devastating condition associated with markedly increased hospital length of stay, cost, mortality, and morbidity. Expanding the role for kidney biopsies in AKI may offer fresh insights into disease heterogeneity, molecular mechanisms, and therapeutic targets. A number of challenges face investigators and clinicians considering research biopsies in AKI: ensuring patient safety, ensuring the ethical conduct of research studies, and maximizing the scientific yield of the kidney tissue obtained. The societal benefits of research that lead to novel strategies for preventing and treating AKI would be enormous. Rethinking our current approach to the role of kidney biopsy for AKI diagnosis and research may be a major step toward the promise of personalized medicine in nephrology.

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

Urinary sediment is used to evaluate patients with possible urinary tract diseases. Currently, numerous protocols are applied to detect dysmorphic red blood cells (RBCs) and renal tubular epithelial cells (RTECs) in urinary sediment. However, distinct protocols are used by nephrologists and medical technologists for specimen concentration and observation, which leads to major discrepancies in the differential counts of formed elements such as dysmorphic RBCs and RTECs and might interfere with an accurate clinical diagnosis. To resolve these problems, we first tested a modified urinalysis protocol with an increased relative centrifuge force and concentration factor in 20 biopsy-confirmed glomerulonephritis patients with haematuria. We successfully improved the recovery ratio of dysmorphic RBCs in clinical specimens from 34.7% to 42.0% (P < 0.001). Furthermore, we confirmed the correlation between counts by the modified urinary protocol and Sysmex UF-1000i urinary flow cytometer (r ≥ 0.898, P < 0.001). A total of 28 types of isomorphic and dysmorphic RBCs were detected using a bright field microscope, with results comparable to those using a standard phase contrast microscope. Finally, we applied Sternheimer stain to enhance the contrast of RTECs in the urinary sediments. We concluded that this modified urinalysis protocol significantly enhanced the quality of urinalysis.

Biomarkers in lupus nephritis

Lupus nephritis (LN) has significant impact on the outcome of patients with systemic lupus erythematosus (SLE). In the absence of any new breakthrough for management of LN over the last few years, using existing treatment modalities in a more effective manner is the mainstay of improving outcomes. For effectively using the drugs, disease activity needs to be assessed accurately and more objectively, which is not possible with present clinical assessment tools. Biomarkers help in accurate assessment of disease activity and enable the physician to individualize the therapy. Conventional disease activity markers have limitations which need to be addressed and research in the area of biomarker discovery in LN has immensely expanded over the last two decades as evident by the literature. Moreover, biomarkers for LN should be different from the markers of overall disease activity as LN requires significant immunosuppression, unlike other non-renal manifestations of SLE. Newly discovered biomarkers exhibit qualities pertaining to different aspects of disease activity and damage. In this review, we discuss the established as well as new biomarkers of SLE in the light of their role in LN diagnosis, follow-up, prediction of renal flare and correlation with renal histology findings.

Clindamycin-induced Kidney Diseases: A Retrospective Analysis of 50 Patients

Objective There are many adverse reactions due to clindamycin, but kidney diseases (acute kidney injury, AKI) are uncommon. However, in recent years, the rate of clindamycin-induced kidney diseases has increased. We analyzed 50 patients with clindamycin-induced kidney diseases retrospectively, and investigated the characteristics of these kidney diseases in order to provide a reference for rational clinical drug use and to reduce drug-induced organ damage. Methods We investigated 50 patients diagnosed with clindamycin-induced kidney diseases retrospectively at the Department of Nephrology, Shandong University Qilu Hospital, from January 2009 to December 2013. The parameters included in our study were age, sex, clinical manifestations, efficacy and prognosis. Results All patients were diagnosed with clindamycin-induced kidney diseases within 48 hours of the application of clindamycin at 1.0-2.0 g/day. The patients included 29 women and 21 men. Most of the enrolled patients were 20-59 years old. Fifty-one patients were diagnosed with AKI stage 3 upon admission. Thirty-three had episodes of gross hematuria, but fever, skin rash and eosinophilia were rare. Urine analysis revealed mild proteinuria and severe tubular dysfunction. In the majority of patients, AKI was severe and required renal replacement therapy, but renal function in all patients had recovered significantly two months after discharge. Conclusion Clindamycin-induced AKI is largely reversible and is associated with episodes of gross hematuria. Clinicians should use clindamycin rationally and reduce the incidence of adverse reactions.

Automated urinalysis with expert review for incidental identification of atypical urothelial cells: An anticipated bladder carcinoma diagnosis

BACKGROUND

The most common diagnostic technique for the detection of malignant/atypical urothelial cells (m/AUC) is urinary cytology (Ucytol). Urinary sediment (Used) examination, often prescribed for asymptomatic, healthy subjects, can incidentally identify suspicious/AUC (s/AUC) in routine daily practice.

METHODS

Unstained, unfixed and uncentrifuged urine samples were analyzed with an automated intelligent microscopy (AIM) system. From January 2010, any incidental identification of s/AUC through expert revision of unclassified cell images was reported, according to internal protocols, as an additional note on the patients' laboratory report. Patients' symptomatology or previous history was unknown to the pathologist. All referrals from January 2010 to December 2014, with the s/AUC note, were reviewed and cross-referenced with Ucytol and histology data from a central database.

RESULTS

Of the 162 patients identified with s/AUC (0.1/1000 samples), 84% (n=136) performed further Ucytol and/or histological examinations. The sensitivity of the identification of non-transitory AUC at Used was 87.5%. Positive histological examinations were 91.2% classified as high-grade urothelial carcinoma.

CONCLUSIONS

Routine Used examination, with an AIM and expert revision, can identify the presence of AUC in a clinical laboratory setting, and for some subjects, may anticipate bladder carcinoma diagnosis.

External Quality Assessment Programs in the US with an emphasis on urinary sediment testing: the College of American Pathologists experience

The College of American Pathologists (CAP) has maintained the highest standards for laboratory medicine through education, evaluation, and certification. One form of External Quality Assurance - proficiency testing (PT) - is the centerpiece of that mission. Over 500 medical and scientific experts oversee CAP PT programs which include more than 600 tests performed by 22,000 laboratories in over 100 countries. It is the most comprehensive laboratory peer-review comparison program in the world. The CAP offers four urine sediment PT products tailored to the needs of different laboratories. Each includes three or four digital images, shipped twice a year. The program is overseen by the Hematology and Clinical Microscopy Resource Committee. Images are graded if there is 80% or greater consensus of either referee or participant laboratories. Failing laboratories must analyze the reasons for the failure, report the results, and initiate corrective action. Over the years, there has been a progressive decline in the number of errors, demonstrating that education and regulatory oversight are major contributors to improved PT performance and, by extension, patient care. The PT urine sediment image databank is a unique resource, representing the consensus of many laboratories. Participant and referee responses identify which morphologic variants are unambiguous and which are more difficult to classify. The PT challenges include discussions of disease pathophysiology and key morphologic features. This teaching component is what helps to set the CAP's program apart. The discussions formed the basis for the Color Atlas of Urinary Sediment published by the CAP in 2010.

The urine sediment as a biomarker of kidney disease

The modern era of medicine has ushered in new diagnostic technologies to assist the clinician in evaluating patients with kidney disease. The birth of automated urine analysis technology and centralized laboratory testing has unfortunately made examination of urine sediment by physicians a rare event. At the same time, identifying novel urine biomarkers for kidney disease has become a research priority in nephrology, and the search for the "renal troponin" has progressed at a fast pace. Despite this, urine sediment examination remains a time-honored test that provides a wealth of information about the patient's kidney condition and performs favorably as a urinary biomarker. It alerts the clinician to the presence of kidney disease and provides diagnostic information that often identifies the compartment of kidney injury. In addition, sediment findings may guide therapy and assist in prognostication. As such, it is premature to abandon urine sediment examination. It may be more appropriate to combine urine sediment examination with new candidate biomarkers that enter clinical practice to create a "diagnostic panel" that provides clinicians with a useful battery of diagnostic tests. To accomplish this, we as nephrologists must encourage continued training and maintenance of competency in urine sediment examination.

Atypical/malignant urothelial cells in routine urinary sediment: worth knowing and reporting

BACKGROUND

Urinary cytology (Ucytol), which is performed in pathology laboratories on fixed and stained samples, represents the gold standard for the identification of atypical/malignant urothelial cells (A/MUC) due to urothelial carcinoma. In this paper we describe three patients in whom A/MUC, due to a bladder carcinoma, were identified with conventional urine sediment (Used) examination on unfixed and unstained samples.

METHODS

Included are urine samples prepared with conventional and standardized techniques as currently used in general clinical laboratories. Samples were examined with phase contrast microscopy. A/MUC were identified according to the criteria currently used for Ucytol.

RESULTS

A/MUC (i.e., cells with unusual and pleomorphic size and shape, increased nuclear/cytoplasmic ratio, increased number of nuclei, irregular nuclear borders and irregular chromatin patterns, either isolated or in clusters) were identified in the urine of three patients, all of whom were found to have bladder carcinoma by cystoscopy.

CONCLUSIONS

At variance with the common and widespread view, A/MUC can also be identified with conventional Used examination, even though Ucytol still represents the gold standard method.

Clindamycin-induced acute kidney injury: large biopsy case series

BACKGROUND

While clindamycin-induced acute kidney injury (AKI) is uncommon, it has occurred more frequently in recent years.

SUMMARY

We investigated 24 patients diagnosed with clindamycin-induced AKI retrospectively. The dosage of clindamycin was 1.0-1.5 g/day. Fifteen patients had episodes of gross hematuria, but fever, skin rash and eosinophilia were rare. Urine analysis revealed mild proteinuria and severe tubular dysfunction. Twenty-three patients were diagnosed with AKI stage 3 upon admission. The clindamycin lymphocyte transformation assay was positive for 63.2% of the patients. Acute interstitial nephritis (AIN) and acute tubular necrosis (ATN) were proven by renal biopsy, and renal insufficiency appeared to result from tubular toxicity and drug crystals. In the majority (87.5%) of the patients, AKI was severe and required renal replacement therapy, but all of their renal function recovered significantly 2 months after discharge. Clindamycin-induced AKI is largely reversible and has episodes of gross hematuria. Renal biopsies confirmed AIN or ATN in these patients.

Biomarkers and updates on pediatrics lupus nephritis

Lupus nephritis is a common complication of systemic lupus erythematosus in children and adolescents. This article reviews the clinical relevance of lupus nephritis and its current treatment. The reader is introduced to novel biomarkers that are expected to improve the management of lupus nephritis in the future, and support the testing of novel medication regimens.

A No Observable Adverse Effects Level (NOAEL) for pigs fed melamine and cyanuric acid

Ingesting melamine adulterated milk products led to kidney stones in many infants in 2008. This differs from the renal failure caused by intratubular crystal formation after co-ingestion of melamine (MEL) and cyanuric acid (CYA) in adulterated pet foods in 2007. To better understand the potential risk of developing crystal nephropathy following co-ingestion of MEL and CYA, we fed 16 weanling pigs 0, 1, 3.3, 10, 33, or 100 mg/kg bw/day of each MEL and CYA, or 200 mg/kg bw/day of either compound individually for 7 days. Crystals were found in the renal medulla and cortex and urine sediments of all pigs fed both MEL and CYA each at 10 mg/kg bw/day (or greater). Crystals were also found in one of the two pigs fed 200 mg/kg bw/day MEL-only. In a 28 day study, 36 weanling pigs were fed 0, 1, or 3.3 mg/kg bw/day of MEL and CYA or 200 mg/kg bw/day MEL-only. Only one of the 3.3 mg/kg MEL and CYA pig kidneys contained crystals. The no-observed-adverse-effect level (NOAEL) for pigs fed MEL and CYA for 28 days was concluded to be 1.0 mg/kg bw/day corresponding to 25 mg/kg (ppm) MEL and 25 mg/kg (ppm) CYA in dry feed.

Generation and characterization of a novel kidney-specific manganese superoxide dismutase knockout mouse

Inactivation of manganese superoxide dismutase (MnSOD), a mitochondrial antioxidant, has been associated with renal disorders and often results in detrimental downstream events that are mechanistically not clear. Development of an animal model that exhibits kidney-specific deficiency of MnSOD would be extremely beneficial in exploring the downstream events that occur following MnSOD inactivation. Using Cre-Lox recombination technology, kidney-specific MnSOD deficient mice (both 100% and 50%) were generated that exhibited low expression of MnSOD in discrete renal cell types and reduced enzymatic activity within the kidney. These kidney-specific 100% KO mice possessed a normal life-span, although it was interesting that the mice were smaller. Consistent with the important role in scavenging superoxide radicals, the kidney-specific KO mice showed a significant increase in oxidative stress (tyrosine nitration) in a gene-dose dependent manner. In addition, loss of MnSOD resulted in mild renal damage (tubular dilation and cell swelling). Hence, this novel mouse model will aid in determining the specific role (local and/or systemic) governed by MnSOD within certain kidney cells. Moreover, these mice will serve as a powerful tool to explore molecular mechanisms that occur downstream of MnSOD inactivation in renal disorders or possibly in other pathologies that rely on normal renal function.

Evaluation and management of hematuria

Causes of hematuria can range from benign conditions such as urinary tract infection to serious conditions such as bladder cancer. In evaluating a patient with hematuria, 3 questions must be answered by the primary care physician: (1) Is it really hematuria? (2) Should this patient with hematuria be worked up, and if so, how? (3) Should this patient with hematuria be referred, and if so, to which specialty? This article addresses these questions. Because uniformly high-quality studies are lacking, the recommendations included in this article are mostly based on expert consensus.

Decreased kidney function and crystal deposition in the tubules after kidney transplant

Adenine phosphoribosyltransferase (APRT) deficiency is an autosomal recessive purine enzyme defect that results in the inability to utilize adenine, which consequently is oxidized by xanthine dehydrogenase to 2,8-dihydroxyadenine (2,8-DHA), an extremely insoluble substance eventually leading to crystalluria, nephrolithiasis, and kidney injury. We describe a case of APRT deficiency not diagnosed until the evaluation of a poorly functioning kidney transplant in a 67-year-old white woman. After the transplant, there was delayed transplant function, urine specimens showed crystals with unusual appearance, and the transplant biopsy specimen showed intratubular obstruction by crystals identified as 2,8-DHA using infrared spectroscopy. APRT enzymatic activity was undetectable in red blood cell lysates, and analysis of the APRT gene showed 1 heterozygous sequence variant, a duplication of T at position 1832. The patient was treated with allopurinol, 300 mg/d, and transplant function progressively normalized. Because patients with undiagnosed APRT deficiency who undergo kidney transplant may risk losing the transplant because of an otherwise treatable disease, increased physician awareness may hasten the diagnosis and limit the morbidity associated with this disease.

An Italian external quality assessment (EQA) program on urinary sediment

BACKGROUND

EQA programs on urinary sediment are rare. We describe an EQA Italian program which started in 2001 and involves today more than 300 laboratories.

METHODS

The program, which started with a questionnaire about the methodological aspects on urinary sediment, includes today four surveys per year. These ask the participants the identification and clinical associations of urinary sediment particles shown by colour images (surveys 1 and 3) and the diagnosis of clinical cases presented by both images and a short clinical history (surveys 2 and 4). The results of each survey are then scored and commented.

RESULTS

Questionnaire (participants = 287): most methodological aspects were not dealt with properly.

IDENTIFICATION

cells, lipids, casts and some contaminants were poorly known. However, when 27 particles were presented for the second time and 16 particles for the third time, the correct identification rate for most of them increased significantly. Clinical associations (No presented = 16): a correct answer was indicated by > or = 84% of participants for all particles but one. Clinical cases (No presented=4): lowest correct identification for urine contamination from genital secretion (77.3%), highest for ureteric stone (94.4%).

CONCLUSIONS

Our program shows that EQA programs are both useful and needed.

The iQ200 Microscopic Analyzer is valuable tool for evaluation of urinary sediment at transplanted patients

The value of urinary cytology in the diagnosis of different pathological conditions in renal transplantation is particularly important. Manual microscopic urinalysis is a high-volume procedure that currently requires significant labour.

Objective: To automate the sediment evaluation and to make this more accurate using the Iris Diagnostics Automated Urine Microscopy Analyzer (iQ200). Our goal was to compare the manual and automated microscopic data to apply iQ200 in renal function monitoring.

Method: The iQ200 uses digital imaging and Auto Analyte Recognition software to classify urine constituents into 12 analyte categories and quantitatively report.

Results: We determined cut-off values of urine particles in every category, which correlated well with manual microscopic results. The iQ200 was more sensitive for pathological casts than manual microscopic analysis. iQ200 helped the operator to differentiate between isomorphic and dismorphic erythrocytes and between lymphocytes and granulocytes, too. Every pathological constituent could be recognized, which is very important for early recognition of renal impairment, graft rejection and urinary tract infection.

Conclusions: The iQ200 system automatically classifies 12 particles, significantly reducing the need for additional sample preparation, manual microscopic review achieving a high degree of standardization in urinalysis.

Preoperative indications for percutaneous nephrolithotripsy in 2009

Abstract Since the first description of percutaneous nephrolithotripsy (PNL) over 30 years ago, the indications for this procedure in the management of upper tract urinary stones has greatly expanded. Despite recent advances in shock wave lithotripsy and ureteroscopic technologies, PNL maintains a dominant role in the management of complex and large volume upper tract stones. The contemporary indications for PNL are reviewed herein.

Interobserver reliability of urine sediment interpretation

BACKGROUND AND OBJECTIVES

Urine sediment interpretation is frequently used in the evaluation of patients with kidney disease. There has been no systematic evaluation of the reliability of this diagnostic maneuver.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Digital photographs of urine sediment images were acquired from 165 consecutive patients being evaluated by the nephrology consultation service at a tertiary care hospital. Urine sediment images of 100 patients were randomly selected; 86 patients had images that were deemed to be of sufficient quality, and one image per patient was chosen for inclusion in an internet-based questionnaire. For each image, the presence or absence of 14 potential urinary structures was ascertained. Ten nephrologists (senior readers [n = 3]: >10 yr of experience; intermediate readers [n = 3]: 1 to 10 yr of experience; and junior readers [n = 4]: first year of practice) completed the questionnaire. For each urinary structure, we measured the rate of complete agreement among the readers as well as the kappa statistic as a marker of agreement beyond chance.

RESULTS

Unanimous agreement was highest (79.1%) regarding the presence of broad and fatty casts and poorest (31.4%) for the identification of dysmorphic red blood cells and white blood cells. Interobserver agreement was best for squamous epithelial cells (kappa = 0.54) and hyaline casts (kappa = 0.52) and worst for transitional epithelial cells (kappa = 0.14) and fatty casts (kappa = 0.06). When assessed within strata of physician experience, interobserver agreement was not associated with seniority.

CONCLUSIONS

Nephrologists achieved slight to moderate agreement in the identification of structures that are commonly observed in the urine sediment.

A qualitative proteome investigation of the sediment portion of human urine: Implications in the biomarker discovery process

Inherent to the biomarker discovery process is a comparative analysis of physiological states. It is therefore critical that the proteome detection protocol does not bias the analysis. With urine, the sediment portion, obtained upon thawing frozen urine, is routinely discarded prior to proteome analysis. However, our results demonstrate that such a practice inadvertently induces bias, having significant implications in the biomarker discovery process. We present the first proteome investigation of human urinary sediments, identifying 60 proteins in this phase by MS. Many sediment proteins were also detected in the urinary supernatant, indicating that several proteins partition between the two phases. This partitioning is dependant on the pH of the sample, as well as the degree of sample agitation. As a consequence of discarding the sediment portion of urine, the concentration of potential candidate biomarkers in the supernatant phase will be altered or, in other instances, may be completely removed from the sample. To minimize this, the pH of all samples should first be normalized, and the samples vigorously vortexed prior to discarding the sediments. For more comprehensive biomarker investigations, we suggest that urinary sediments be analyzed along with the supernatant proteins.

How to improve the teaching of urine microscopy

BACKGROUND

Urinary microscopy is difficult to teach. This paper describes a 1-day course on urine microscopy, which was based on both theoretical and practical sessions at the microscope, during which real urine samples were examined.

METHODS

The course was based on: a) an introductory presentation with slides on the main components of urinary sediments and their clinical correlates; b) examination of fixed urine samples under the guidance of two experts; and c) the use of two microscopes, each equipped with a co-observation device for up to 15 observers.

RESULTS

Throughout 2005, four courses were held in four Italian towns. Altogether, there were 97 participants (20-27 per course) from 75 laboratories, all graduates with wide but variable experience in the field. During each course, 17-22 urinary sediment components were shown by both bright-field and phase-contrast microscopy and, when indicated, by polarized light. Tests set before and after the course showed a significant improvement (p<0.01) in the identification of erythrocyte subtypes, epithelial cells, fatty components, various types of casts and drug crystals. A questionnaire conducted with participants by phone several months after the course demonstrated that 51.6% and 32.3% of laboratories have introduced or formally requested phase-contrast and polarized-light microscopy, respectively; 45.2% have changed the terminology for urinary epithelial cells; and 87.1% have identified for the first time urinary sediment components that were not recognized or not considered before the course.

CONCLUSIONS

Our course demonstrates that it is possible to improve the teaching of urinary microscopy.

Polyomavirus nephropathy in native kidneys and renal allografts: an update on an escalating threat

Polyomavirus nephropathy, also termed BK-virus nephropathy (BKN) after the main causative agent, the polyoma-BK-virus strain, is a significant complication after kidney transplantation. BKN is the most common viral infection that affects renal allografts with a prevalence of 1-9% on average 8-13 months post surgery. It can also occur sporadically in native kidneys. Viral nephropathy is caused by the (re)activation of latent BK viruses that enter into a replicative cycle under sustained and intensive immunosuppression. Pure productive kidney infections with JC- and SV-40 polyomaviruses are exceptionally rare. BKN is morphologically defined by the presence of intranuclear viral inclusion bodies in epithelial cells and tubular injury, which is the morphological correlate for renal dysfunction. Renal disease can progress through different histologic stages (from early BKN stage A to late fibrotic stage C) that carry prognostic significance; disease stages B and C often result in chronic kidney (allograft) dysfunction and end-stage renal disease. The clinical goal is to diagnose viral nephropathy in disease stage A and to limit chronic renal injury. Strategies to recognize, classify, and manage BKN are critically discussed including ancillary techniques for risk assessment and patient monitoring: (i) urine cytology and the search for so-called 'decoy cells'; (ii) PCR analyses for viral load measurements in the plasma and urine; and (iii) negative staining urine electron microscopy to identify viral particles.

Fast fingerprinting by MALDI-TOF mass spectrometry of urinary sediment glycosphingolipids in Fabry disease

Fabry disease (FD) is an X-linked inborn error of glycosphingolipid (GSL) metabolism, caused by a deficiency of the lysosomal alpha-galactosidase A, which results in high levels in lysosomes and biological fluids of globotriaosylceramide (Gb3) and digalactosylceramide (Ga2), also known as galabiosylceramide. We report here a detailed study of the molecular species of GSLs in urinary samples obtained from hemizygous and heterozygous patients by use of matrix-assisted laser desorption ionisation and tandem mass spectrometry (MALDI-MS-MS). Twenty-two and fifteen molecular species were identified in the globotriaosylceramide and digalabiosylceramide series, respectively. The major sphingoid base was sphingosine (d18:1), and dihydrosphingosine (C18:0) and sphingadienine (d18:2) were also present. The molecular profiles obtained by MALDI-TOF-MS enabled us to show significant differences between GSLs composition for young, adult or atypic hemizygote and heterozygote patients. Thus, MALDI-TOF-MS and MS-MS proved a powerful tool for screening a population of patients with clinical signs suggestive of FD by direct and rapid GSL fingerprinting and identification, and for study of the biological processes occurring in glycosphingolipid accumulation.