Urine cytology in renal glomerular disease and value of G1 cell in the diagnosis of glomerular bleeding

Current state of the morphological assessment of urinary erythrocytes in The Netherlands: a nation-wide questionnaire

Background The morphological assessment of urinary erythrocytes (uRBC) is a convenient screening tool for the differentiation of nephrological (dysmorphic) and urological (isomorphic) causes of hematuria. Considering the morphological heterogeneity, this analysis is often perceived as difficult. There is no clear (inter)national consensus and there is a lack of external quality assessment programs. To gain insight into the heterogeneity within and between laboratories, we scrutinized the current state of this analysis in Dutch medical laboratories. Methods The laboratories, affiliated with the Dutch Foundation for Quality Assessment in Medical Laboratories, were invited to participate in a web-based survey, consisting of two questionnaires. The first one provided information about the institution and laboratory organization, and the second explored the variability in the morphological analysis of uRBC on the basis of categorization of 160 uRBC images. Statistical analysis was premised on binomial significance testing and principal component analysis. Results Nearly one third of the Dutch medical laboratories (65/191) with 167 staff members participated in the survey. Most of these laboratories (83%) were an integral part of secondary care. The statistical analysis of the evaluations of the participants in comparison to the consensus (three experts from two different medical laboratories) suggested a great degree of heterogeneity in the agreement. Nearly half of the participants consciously disagreed with the consensus, whereas one fifth demonstrated a random relationship with it. Conclusions In Dutch medical laboratories, results from morphological analysis of uRBC are heterogeneous, which point out the necessity for standardization and harmonization.

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.

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.

'Cannibalism' (cell phagocytosis) does not differentiate reactive renal tubular cells from urothelial carcinoma cells

OBJECTIVE

Cannibalism of one cell by another in voided urine cytology has been considered a cytological feature for differentiating urothelial carcinoma (UC) from benign lesions. Recently, however, we observed cannibalism in voided urine obtained from patients with renal glomerular disease (RGD). The purpose of this study was to determine the cytomorphological and immunocytochemical characteristics of cannibalism in voided urine from RGD.

METHODS

Seventy cytology specimens of voided urine were examined and the findings were compared with the histological findings. In addition, we compared the cytomorphological and immunocytochemical differences in cannibalism found in RGD and cases of UC selected as showing cannabilism.

RESULTS

Cannibalism in voided urine was found in three (5.5%) of 55 RGD cases. The finding was measured as (1+) < 5 cells, (2+) 5-20 cells, and (3+) > 20 cells and was (1+) in all three RGD cases, compared with 6.7%, 60% and 33.3% respectively in 15 UC cases. Differences in low cellularity cases (1+) and moderate to high cellularity cases (2+ or 3+) were statistically significant between RGD (3 and 0) and UC (1 and 14) (P=0.005). The maximum diameter of cannibalized cells in RGD was 24.3-33.0 microm (mean 29.8 microm) versus 18.0-30.4 microm (mean 23.3 microm) in UC (P=0.004). Necrosis and isomorphic erythrocytes were absent in RGD, but were found in 46.7% and 86.7%, respectively, of UC cases (P=0.245 and P=0.012). Dysmorphic erythrocytes were identified in all three cases with RGD and 13.3% of UC (P=0.012). Vimentin reactivity was found in all cases with cannibalism in RGD, but never in UC (P=0.001).

CONCLUSIONS

Our results demonstrated that cannibalism in voided urine is present not only in UC but also in RGD. Furthermore, we showed that cellularity of cannibalism, vimentin reactivity and background differed significantly and can be used for differential diagnosis between the two groups.

A useful new classification of dysmorphic urinary erythrocytes

BACKGROUND

Among dysmorphic urinary erythrocytes (D cells), G1 cells or doughnut-shaped erythrocytes with one or more blebs are considered to be reliable markers for glomerular diseases. However, although there are many D cells with cytoplasmic color loss and without blebs in the urinary sediment, the significance of these cells is not clear. In this study, we devised a classification system for D cells and examined the relation between these cell types and urinalysis data.

METHODS

We classified D cells into three types (D1, D2, and D3 cells): D1 cells showed a ring-like shape and severe loss of cytoplasmic color with protrusions or blebs; D2 cells showed a doughnut-like shape and moderate cytoplasmic color loss with protrusions or blebs; and D3 cells showed a doughnut-like shape and mild cytoplasmic color loss without protrusions or blebs. We calculated the numbers of D cells of each type in 45 patients with glomerular diseases and in 303 general outpatients. This was done by bright-field microscopy modified for the analysis of urinary sediment, and we also examined the significance of these cell types.

RESULTS

In the 45 patients with glomerular diseases, the numbers of D1, D2, and D3 cells correlated with urine levels of proteinuria and hematuria and numbers of cellular and fatty casts. Numbers of D1 and D2 cells correlated with urine concentrations of albumin and N-acetyl-beta-D-glucosaminidase, and the proportions of D1 and D2 cells in D cells increased with the activity of glomerular diseases classified by urinalysis data. Only the number of D1 cells correlated with the urine concentration of potassium, which may increase in hemolysis. In the 303 outpatients, the sensitivity of D3 cells and D1 and/or D2 cells (G1 cells) was 73% and 46%, respectively, for the detection of glomerular diseases and the specificity was 93% and 99%, respectively.

CONCLUSIONS

These data indicate that the D3 cell is a sensitive marker for glomerular diseases, and that D1 and/or D2 cells are markers for severe glomerular diseases.

Repair renal tubular cells: A potential false-positive diagnosis in urine cytology

To study the cytopathology of repair renal tubular cells (RRTCs), the Papanicolaou-stained urine sediments of 371 patients with mild and moderate renal tubular injuries were reviewed. In 46 cases, the urine sediments showed, in addition to a mild or moderate increase in number of RTCs, a few isolated and clustered RRTCs that displayed well- or ill-defined, variably abundant, granular or vacuolated cytoplasm; slightly pleomorphic nuclei; and conspicuous or prominent nucleoli. A spectrum of nuclear changes ranging from mild to moderate atypias and/or severe atypia were present in many cases. These RRTCs stained strongly positively with vimentin antibody in 92.3% of the cases.