The urine doesn’t lie: understanding the urinanalysis


If you’ve ever wondered about how to differentiate sediment on a urinanalysis (you’d have to be a med student!), check out this Renal Fellow Network post about acanthocytes and other abnormal RBCs It’s a helpful starting point. For a more detailed and thorough reference for a differential of urinanalysis findings, I’d refer to this Access Medicine page. It has a neat graphic that helps to conceptualize a lot of the possible crystal findings:

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Urinanalysis is a fundamental diagnostic test that can tell us tons about kidney function. For example, red blood cells in the urine, depending on what shape they are, how many of them, etc., may indicate glomerular disease (nephritis, I’m looking at you). “Muddy brown” casts, on the other hand, are a sign of acute tubular necrosis. And in the case of UTIs and pyelonephritis, you can sometimes see the actual bacteria on the slide.

Before microscopes and special stains, though, there was uroscopy–the art of diagnosis through examination of the urine, by looking, smelling, and yes, tasting, of urine. Hippocrates devoted an entire section to it in his Book of Prognostics. Boiling urine, adding components to it…physicians were inventive. Uroscopy was not only a way for physicians to evaluate patients, but a way for patients to evaluate the competence of their doctors, as this description from Wonders and Marvels shows.


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