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

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 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.