Misidentification of epithelial renal tubular cells as decoy cells in the urinary sediment of a kidney transplant recipient: the importance of adequate clinical information.

The examination of the urinary sediment of a kidney transplant recipient, carried out in blind conditions, showed the presence of a moderate number of cells which were identified as decoy cells. Most frequently these cells are a marker of BK polyomavirus reactivation, which can lead to BK virus nephropathy and graft loss. However, the patient's clinical history, the absence of BK viremia, and the renal biopsy findings excluded this condition. The careful examination of the renal biopsy demonstrated a severe tubular damage with cells resembling those identified in the urine as decoy cells. This paper is the first which demonstrates that damaged renal tubular epithelial cells can be misidentified as decoy cells. In addition, it highlights the importance of supplying adequate clinical information for a correct urinary sediment examination.

A morphological classification of the fat particles found in the urinary sediment of patients with Fabry disease.

OBJECTIVES: The search in the urinary sediment (U-sed) of fat particles with peculiar morphology is a simple and inexpensive tool for the diagnosis of Fabry disease (FD) nephropathy. In this study we investigated the morphology of a high number of such fat particles with the aim to obtain a morphological classification to be used for their identification. METHODS: Study of the morphology of fat particles in the U-sed of a cohort of FD patients using: bright field plus phase contrast microscopy (BF + PC), polarized light microscopy (POL), and transmission electron microscopy (TEM). Comparison of these results with those obtained for the fat particles seen in the U-sed of a control group (CG) of patients with non-FD glomerulopathies. RESULTS: FD: 18 U-sed from six patients (three samples/patient) were prospectively investigated and 506 fat particles identified. With BF + PC, these were classified in eight morphological categories (seven of which were confirmed by TEM), and with POL in 10 others. CG: eight U-sed from eight patients were investigated and 281 fat particles identified. These fell into four BF + PC morphological categories and into eight POL categories. While some categories were significantly more frequent in FD others were more frequent in the CG. CONCLUSIONS: Our study demonstrates that 1. The morphology of fat particles found in the U-sed of FD patients is much wider and complex than that described so far 2. Several significant differences exist in the morphology of such fat particles between FD and CG patients.

Spheroplasts, poorly known but clinically relevant particles of urinary sediment.

BACKGROUND: In two patients under treatment with various antibiotics, spheroplasts were detected with an automated urine sediment analyzer. METHODS: Urinalysis was performed by an AutionMAX AX 4030-sediMAX platform. RESULTS: Spheroplasts can be easily misclassified as yeasts or erythrocytes, but when automated urine sediment analyzers are used by well-trained, and experienced operators they can be correctly identified and classified. CONCLUSION: Appropriate training of urine laboratory professionals in spheroplast detection and association with UTI, together with timely communication with the microbiologist and caring clinician, will provide prompt targeted treatment.

The First Ever External Quality Assessment Program on Urinary Sediment in a Country of Sub-Saharan Africa Based on New Smartphone Technologies.

BACKGROUND: External Quality Assessment (EQA) programs on urinary sediment (U-sed) examination are recommended by international guidelines to improve the quality of this diagnostic tool. However, no such programs have been carried out so far in developing countries of sub-Saharan Africa. This paper describes an EQA program on U-sed which was realized in 2017 and 2018 by means of innovative communication technologies in Benin Republic, a small country of West Africa. METHODS: On Monday morning, weekly in 2017 and fortnightly in 2018, the image of one U-sed element was sent from Italy with a smartphone, via WhatsApp application, to a group of 13 professionals (11 bachelors of science, 2 medical doctors) working in different institutions of Benin Republic. The image showed one U-sed element, for which the participants were asked the identification and, in 2018, also a clinical association. RESULTS: The images of 33 elements were submitted over the two-year period. Particle identification. Altogether 283 answers were received (8.5 ± 2.3/single image), 200 of which were correct (70.7%), 53 incorrect (18.7%), 17 partially correct (6.0%), and 13 "I don't know" (4.6%). Correct identification of elements presented twice (2nd answer vs. 1st). No change: 9/18 (50.0%); improvement: 5/18 (27.8%); worsening: 4/18 (22.2%). Clinical association. Correct answers: 8/17 (47%); incorrect: 8/17 (47.0%); no answer: 1/17 (5.6%). CONCLUSIONS: This paper demonstrates: 1. The need and utility of an EQA program on U-sed in developing countries of sub-Saharan Africa; 2. The feasibility of such programs by means of easily available and inexpensive smartphone applications.

Glomerular isolated microscopic hematuria: urinary features and long term follow-up of a selected cohort of patients.

BACKGROUND: Isolated microscopic hematuria is a condition characterized by the presence in the urine of an "abnormal" number of erythrocytes in the absence of proteinuria. Several studies have been published on this condition, but with heterogeneous inclusion criteria and variable outcomes at follow-up. In this retrospective study, we describe a selected and homogenous cohort of patients who presented with isolated microscopic hematuria of glomerular origin. METHODS: We included in the study patients with isolated microscopic hematuria of glomerular origin (> 1 erythrocyte/high power field at 400× and ≥ 40% dysmorphic erythrocytes and/or ≥ 5% acanthocytes and proteinuria ≤ 150 mg/24 h) with a follow-up of > 60 months from the first documentation of microscopic hematuria. RESULTS: Forty-two patients (M 12, F 30, age at presentation 14-68 years, eGFR < 60 ml/min/1.73 m2: 1 patient) were included. During a medium term follow-up, microscopic hematuria was persistent in 25 patients (59.5%), transiently absent in 17 (40.5%), always glomerular in 16 patients (38.1%), and occasionally non-glomerular in 26 (61.9%); proteinuria, observed in 16 patients (38.1%), was always transient and < 500 mg/24 h. At the end of a follow-up of 181.8 ± 97.9 (median 168) months, only 2 patients (4.8%) had eGFR < 60 ml/min/1.73 m2, one of whom had reduced eGFR already at presentation. CONCLUSIONS: This study on a small but selected and homogeneous cohort of patients with isolated microscopic hematuria of glomerular origin demonstrates that urinary features can transiently change over time and that the renal outcome is good.

Advances in Urine Microscopy.

Urine microscopy is an important tool for the diagnosis and management of several conditions affecting the kidneys and urinary tract. In this review, we describe the automated instruments, based either on flow cytometry or digitized microscopy, that are currently in use in large clinical laboratories. These tools allow the examination of large numbers of samples in short periods. We also discuss manual urinary microscopy commonly performed by nephrologists, which we encourage. After discussing the advantages of phase contrast microscopy over bright field microscopy, we describe the advancements of urine microscopy in various clinical conditions. These include persistent isolated microscopic hematuria (which can be classified as glomerular or nonglomerular on the basis of urinary erythrocyte morphology), drug- and toxin-related cystalluria (which can be a clue for the diagnosis of acute kidney injury associated with intrarenal crystal precipitation), and some inherited conditions (eg, adenine phosphoribosyltransferase deficiency, which is associated with 2,8-dihydroxyadenine crystalluria, and Fabry disease, which is characterized by unique urinary lamellated fatty particles). Finally, we describe the utility of identifying "decoy cells" and atypical malignant cells, which can be easily done with phase contrast microscopy in unfixed samples.

The Italian External Quality Assessment (EQA) program on urinary sediment: results of the period 2012-2015.

BACKGROUND: Manual microscopy still represents the gold standard for urinary sediment (US) examination. We report the results obtained in the period 2012-2015 by the EQA Italian program on US, which today involves about 260 laboratories. METHODS: The program includes four surveys per year. In two surveys, participants are asked to supply identification and clinical association of US particles. In two other surveys, they are asked to supply the diagnosis of clinical cases, presented with images, some key laboratory findings and a short clinical history. Sixty-six images of US particles (21 cells, 2 lipids, 21 casts, 10 crystals, 3 microorganisms, 15 contaminants) and seven clinical cases were presented. RESULTS: The correct identification rate for each category of particles, in decreasing order, was: micro-organisms (mean±SD: 92.4%±4.5%), lipids (92.0%±1.8%), casts (82.8%±8.8%), crystals (79.4%±29.8%), cells (77.3%±13.5%), and contaminants (70.9%±22.2%). For 13 particles, a correct clinical association was indicated by 91.5%±11.7% of participants, while it was 52.7% for particles associated with urinary tract infection. For clinical cases, due to a high rate of particles misidentification, only 44.3%±10.1% of participants achieved access to clinical diagnosis, which was then correctly indicated by 92.5%±5.3% of them. CONCLUSIONS: The results of the EQA program confirm that, while some US particles are well known in terms of identification, clinical association and clinical meaning, others particles still are not, and this represents an important reason to encourage EQA programs on US.

Evaluation of clinical cases in External Quality Assessment Scheme (EQAS) for the urinary sediment.

BACKGROUND: The few available External Quality Assessment (EQA) programs on urinary sediment rarely include an evaluation of clinical cases. The present paper provides a descriptive analysis of clinical cases included in the Italian EQA program on urinary sediment. METHODS: Ten cases were presented over a 5-year period (2007-2011). Each clinical case included a brief clinical history, some key laboratory data and four key urinary sediment particles obtained by phase contrast microscopy. The clinical diagnoses indicated by participants, chosen among four or five proposed, were evaluated only for those who had been able to correctly identify all four urinary sediment particles. The results of each survey were then evaluated, scored and commented on. RESULTS: The numbers of participants for the 10 surveys ranged from 268 to 325. Throughout surveys, only 63.9%±17.0% (range 39.6%-88.7%) of participants achieved access to clinical diagnosis. Of these, 90.2%±8.5% (range 73.7%-98.1%) were able to indicate the correct diagnosis. CONCLUSIONS: Our findings demonstrate that once the correct identification of urinary sediment particles is obtained, most participants are able to associate urinary findings with the respective clinical conditions, thus establishing the correct diagnosis.

Waxy casts in the urinary sediment of patients with different types of glomerular diseases: results of a prospective study.

BACKGROUND: Casts are well known components of the urinary sediment. For most casts, the clinical associations are known and demonstrated, while for waxy casts they are totally unknown. METHODS: Prospective study for the search and count of waxy casts in the urinary sediment of patients with different types of glomerular diseases. RESULTS: Waxy casts were found in 39 out of 287 patients (13.6%), mostly in low number (1 to 9 out of 100 casts evaluated/sample). They were frequent in postinfectious glomerulonephritis and renal amyloidosis (5/9 patients, 44.5%, p=0.02 for each condition), while they were rare in membranous nephropathy (4/67 patients, 6.0%, 0.04) and absent in focal segmental glomerulosclerosis (0/23 patients, p=0.05). Waxy casts were associated significantly with higher serum creatinine levels (p<0.0001), with the presence of >1 leukocyte/HPF, granular casts and leukocytic casts (p=0.001 to 0.008) and with higher numbers of erythrocytes, leukocytes, renal tubular epithelial cells, granular casts, epithelial casts, and leukocytic casts (p<0.0001 to=0.03). CONCLUSIONS: Waxy casts are uncommon and few in patients with glomerular diseases and are associated with impaired renal function and with several other structures of the urinary sediment.

Acute interstitial nephritis after amoxycillin with hematuria, red blood cell casts and hematuria-induced acute tubular injury.

A 62-year-old Caucasian man is described who developed acute kidney injury (AKI) and gross hematuria after a course with amoxycillin. At admission, urinalysis showed mild proteinuria, marked microscopic hematuria and cylindruria, which also included red blood cell casts. At renal biopsy an acute interstitial nephritis (AIN) was found, which was associated with many intratubular red blood cells and red blood cell casts, consequent acute tubular injury and red blood cell phagocytosis by tubular cells. After a course with corticosteroids, renal function partly recovered. This case demonstrates that red blood cell cylindruria, red blood cell intratubular casts and red blood cell-induced tubular injury can also be observed in patients with acute interstitial nephritis and not only in patients with glomerulonephritis as described so far.

Adenine phosphoribosyltransferase deficiency: an underdiagnosed cause of lithiasis and renal failure.

We describe an infant affected by adenine phosphoribosyltransferase (APRT) deficiency diagnosed at 18 months of age with a de novo mutation that has not been previously reported. APRT deficiency is a rare defect of uric acid catabolism that leads to the accumulation of 2,8 dihydroxyadenine (2,8-DHA), a highly insoluble substance excreted by the kidneys that may precipitate in urine and form stones. The child suffered from renal colic due to a stone found in the peno-scrotal junction of the bulbar urethra. Stone spectrophotometric analysis allowed us to diagnose the disease and start kidney-saving therapy in order to avoid irreversible chronic kidney damage. APRT deficiency should always be considered in the differential diagnosis of pediatric urolithiasis.

Urinary red blood cells: not only glomerular or nonglomerular.

Two main types of red blood cells, isomorphic and dysmorphic, are found in the urine sediment, indicating nonglomerular and glomerular hematuria, respectively. Occasionally, however, other types of red blood cells such as sickle cells, anisocytes, poikilocytes, elliptocytes and dacryocytes can be seen in the urine sediment of patients with hematuria. This paper describes such cases reported in the literature in which such unusual urinary red blood cells have been found and the experience of the authors on this subject.

Crystalluria: prevalence, different types of crystals and the role of infrared spectroscopy.

BACKGROUND: Studies on the frequency of the different types of urinary crystals and the role of Fourier transform infrared microspectroscopy (FTIRM) for identification are few. We describe the results of a retrospective study on the prevalence and typology of crystalluria and on the role of FTIRM. METHODS: Urinary crystals were identified using the combined knowledge of crystal morphology, birefringence features and urine pH (combined approach). When this was inconclusive, FTIRM was performed. RESULTS: Crystalluria was found in 807 out of 9834 samples (8.2%). In 793, the combined approach identified "typical" crystals, while in 14 FTIRM was needed to identify "atypical" crystals. Among "typical crystals", calcium oxalate (75.9%), uric acid (25.9%) and amorphous urates (7.9%), alone or in combination, were the most frequent. Brushite, ammonium biurate and cystine were the most rare (0.1%-0.7%). FTIRM identified 12 of 14 atypical crystals: three crystals were due to a drug (amoxicillin, indinavir, doubtful phenytoloxamine); four were due to calcium oxalate mono- or bihydrate, uric acid bihydrate or struvite; five were due to calcium carbonate, Tamm-Horsfall glycoprotein, or rare salt combinations. CONCLUSIONS: Crystalluria is not rare and most crystals can be identified by the combined approach. Occasionally, identification of crystals will require FTIRM.

A theoretical and practical course on urine microscopy in Nigeria: a model for nephrological skill transfer.

BACKGROUND: In the developing world, the diagnostic power of nephrologists is heavily limited by financial, technical and human resource constraints. Urine microscopy (UM) is a basic, inexpensive and relatively simple diagnostic tool, which supplies irreplaceable information. Recently, a theoretical and practical course on UM was organized during the 22nd annual meeting of the Nigerian Society of Nephrology. METHODS: The 2-day course was based on power point presentations and on examination of true urine samples by means of a microscope equipped with phase contrast, polarized light and a video camera for projection of the findings. RESULTS: The presentations described were the methodology, the particles of the urine sediment and their clinical interpretation, the urine sediment in different clinical conditions, and 12 clinical cases, which demonstrated the value of UM in clinical practice. Practical sessions showed the most important urine particles, and how they could be identified and combined into urine profiles. More than 97% of the participants found the course to be useful and practicable and a UM program was actually started in 1 Nigerian center a few days after the course. CONCLUSION: This course demonstrated that nephrological skills can be transferred from the developed to the developing world without large financial investments.

Urinary balantidiasis: diagnosis at a glance by urine sediment examination.

A 56-year-old Caucasian man with non-Hodgkin's lymphoma, who had previously been treated with prolonged intensive chemotherapy, was hospitalized for an acute and reversible kidney injury of multifactorial origin. The urinary sediment examination, performed daily, demonstrated the presence of renal tubular cells and renal tubular cell casts. Surprisingly, it also showed the presence of trophozoites of the protozoan Balantidium coli, which were identified on the basis of its characteristic morphology and rapid movements across the slide, and transient leukocyturia. The patient was asymptomatic, his medical history was negative for gastrointestinal disease, and no Balantidium coli was found in the feces. In spite of this, due to the previous chemotherapy, the patient was treated with oral metrodinazole. Only one other case with Balantidium coli in the urine sediment has been described so far and this paper stresses the importance of the examination of the urinary sediment.

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.