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For the Love of Urinalysis: The Beauty of Clinical Microscopy of Urine Sediment

byZEISS Microscopy 12 November 2020 3 min read

Introduction

For the Love of Urinalysis

An interview with a professor passionate about clinical microscopy of urine sediments

Dr. José Antonio Tesser Poloni is well established in the field of urinalysis. He is a professor of laboratory medicine specializing in disciplines related to clinical microscopy, such as urinalysis and clinical parasitology, at Universidade do Vale do Rio dos Sinos (UNISINOS), São Leopoldo-Brazil. Additionally, he is a consultant for the External Quality Assessment Program on Urinalysis at Controllab, Rio de Janeiro-Brazil.

In this interview, Dr. Poloni shares how he entered the field of urinalysis and some select microscopy work using ZEISS Primostar.

Cryptococcus spp. encapsuled yeasts entrapped within the proteinaceous matrix of the cast observed in the urine sediment. Imaged using ZEISS Primostar with phase contrast. — *Cryptococcus spp.* encapsuled yeasts entrapped within the proteinaceous matrix of the cast observed in the urine sediment. Imaged using ZEISS Primostar with phase contrast.

Daily Use of Microscopy

Both in Teaching and for Clinical Diagnostics

I give classes at the university related to clinical microscopy. We use microscopes in our classes to teach about the structures that have clinical relevance and also how to correctly perform clinical analysis evaluations.

I also work daily at the Laboratório de Análises Clínicas Carlos Franco Voegeli at Santa Casa de Misericórdia de Porto Alegre performing urine sediment microscopy of samples from patients with a wide variety of clinical conditions, including a large number of samples from kidney allograft recipients and from patients with severe kidney diseases. This work is extremely interesting and also challenging due to the frequency of finding unusual structures, some of which have never previously been reported. My use of phase contrast and polarized light filters was very helpful as these are the gold standard resources to properly identify particles of clinical interest like dysmorphic erythrocytes, urinary casts, lipid droplets and urinary crystals.

I remember vividly the first time I observed a urine sample on the microscope and I saw a beautiful erythrocyte in movement. I could clearly, for the first time, understand the biconcave morphology of this cell. In the blood slides, they are stained and immobile, much different from the real morphology. During urine sediment analysis, I observed that incredible structure in full detail! It was an amazing experience to me.

Dr. José Antonio Tesser Poloni
Universidade do Vale do Rio dos Sinos (UNISINOS), São Leopoldo-Brazil

The Beauty of Urine Crystals

Visualized using Polarized Light Microscopy

Uric acid crystals in urine sediment seen under polarized light microscopy with ZEISS Primostar

The Power of Polarized Light Microscopy

Crystals in urine are a relatively common finding; for example, calcium oxalate bi-hydrated crystals are commonly seen and I remember observing them during my classes at university. Crystals in urine sediment have a wide variety of forms and composition and can have clinical significance.

But, there is something very special about crystals in urine sediment when you observe their characteristics under polarized light! It’s a totally different experience. Some crystals under polarized light (like uric acid crystals, for example) have a strong and beautiful polychromatic birefringence that completely catches the attention to anyone that has the chance to observe it. The use of these filters, besides contributing to the quality of the work, can also attract the attention of professionals and students.

Trypanosoma cruzi trypomastigotes in the urine sediment imaged with phase contrast microscopy. — *Trypanosoma cruzi* trypomastigotes in the urine sediment imaged with phase contrast microscopy.

Memorable Moment in a Urinalysis Career

I have many memorable moments during my career with urinalysis. Regarding one impressive urinary finding, I had the chance to identify Trypanosoma cruzi trypomastigotes (a parasite from the blood and tissues) in the urine sediment of a kidney allograft recipient. I made photos and videos of the parasite in the urine sediment and the case report was published. Until today, this is a unique report in the medical literature on Trypanosoma cruzi trypomastigotes in the urine sediment. I am sure this remarkable moment was only possible due to the use of phase contrast filters. As the parasite is extremely small and thin and the urine sediment is unstained, I was able to find it only because of the phase contrast revealing the presence of the parasite in movement on the slide. With bright field only, it was almost impossible to see the parasite on the sample.

My advice for those who understand that they are interested in microscopy is to dedicate themselves. After that, find what subject within the microscopic world interests you and then, dive in and learn everything you can! I discovered urine microscopy at my university but it was only in the laboratory working with the microscope that I really found my passion. I believe you only do your best if you work with something you love and I love urinalysis!

Dr. José Antonio Tesser Poloni
Universidade do Vale do Rio dos Sinos (UNISINOS), São Leopoldo-Brazil