Gender's equality in evaluation of urine particles: Results of a multicenter study of the Italian Urinalysis Group

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.

Urinary cylinders: what pediatrician and nephrologist need to know

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

Validation and verification of automated urine particle analysers

There is often uncertainty on how validation and verification of newly introduced tests should be conducted, and there is a real risk of verification becoming a meaningless ritual, rather than a useful exercise. This article reviews the literature and makes recommendations regarding the validation and verification of automated urine particles analysers. A generic practical approach to verification is also recommended. For many analysers, the accuracy of white blood cells, epithelial cells and bacterial counts is corroborated by a number of independent evaluations; thus, any verification laboratory work could be significantly scaled down. Conversely, in the scenario that automated urine microscopy is used as a screening test to reduce the number of urines cultured, the extremely variable performance reported in the literature requires a full-scale verification to define the optimal cut-off values that give a sensitivity of >98% with the local settings and circumstances. With some analysers, the risk of carry-over also needs to be assessed, as part of the verification process, and exclusion criteria (urines requiring culture regardless of the microscopy results) need to be well defined, as there are patients or specimen types for which the performance of microscopy as a screening test may not be adequate.

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.

UriSed - Preliminary reference intervals and optimal method for urine sediment analysis in newborns and infants

OBJECTIVES

The aim of this study was to establish reference intervals for urine sediment in newborns and infants in the second month of life for the UriSed automated analyser and for bright field microscopy. We also aimed to provide an optimal protocol for UriSed analysis, which best corresponds to the results of manual microscopy.

DESIGN AND METHODS

Urine sediment analyses of 75 healthy newborns and infants in the second month of life were performed by manual microscopy and UriSed automated analyser (two modes: 15 and 20 images per sample). Images were then reviewed and manually corrected by an operator when needed.

RESULTS

We observed statistically significant differences between bright-field microscopy and UriSed (when manual correction was not performed) for squamous epithelial cells and red blood cells counts (P<0.0001). There were no differences based on the number of images per sample (P>0.05). Upper reference values for bright-field microscopy and UriSed analyser taking 15 images per sample with manual correction (method we recommend) were as follows: squamous epithelial cells: microscope 8.7×10(6)/l, UriSed 6.4×10(6)/l, non-squamous epithelial cells: microscope 4.3×10(6)/l, UriSed 3.9×10(6)/l; erythrocytes: microscope 5.9×10(6)/l, UriSed: 4.6×10(6)/l; leukocytes: microscope 8.6×10(6)/l, UriSed 9.9×10(6)/l; hyaline casts: microscope 0×10(6)/l, UriSed (no correction) 0.7×10(6)/l.

CONCLUSIONS

We established preliminary reference intervals for urine sediment analysis in newborns and infants for UriSed and bright-field microscopy. We concluded that for routine laboratory examination of non-pathological urine it is enough to use the faster mode, with 15 images per sample, followed by a manual correction.