Leukocyte cylinder

Urinalysis has been used for thousands of years. It is the first laboratory test in medicine (Echeverry 2010).

Leukocyte casts are a type of cell cast and are commonly found in the urine in cases of kidney infections (UroSurf2017).

When it comes to casts, a distinction is made between:

• Hyaline casts: These have the same diagnostic significance as proteinuria. They can therefore also occur in healthy individuals after physical exertion.
• Red blood cell casts: These are found in the urine in cases of glomerulonephritis.
• Leukocyte casts: These are found in cases of chronic pyelonephritis.
• Epithelial casts: They are not specific to any particular kidney disease (Herold 2025)

Leukocyte casts are found in the urine in cases of

• chronic pyelonephritis in approximately 80% of affected individuals (Herold 2025 / Kasper 2015)
• Healthy individuals
• Fever
• dehydration
• acute heart failure (Caleffi 2015)

When leukocyturia and leukocyte casts occur together in the urine, this indicates serious involvement of the renal parenchyma (Guideline 2021).

Leukocyte casts are mucoprotein casts containing leukocytes (UroSurf2017). They consist of Tamm-Horsfall glycoprotein (THG) (Caleffi 2015).

In cases of kidney disease, they can enter the urine both via trans-tubular transport and through glomerular migration (UroSurf2017).

Leukocyte casts can easily be confused with epithelial casts, as both are similar in size. However, epithelial casts contain larger, round nuclei, whereas leukocyte casts contain segmented nuclei (UroSurf2017).

1. Caleffi, A., & Lippi, G. (2015). Cylindruria. Clin Chem Lab Med. doi: 10.1515/cclm-2015-0480.
2. Echeverry, G., Hortin, GL, Rai, AJ (2010). Introduction to Urinalysis: Historical Perspectives and Clinical Applications. In: Rai, A. (Ed.) The Urinary Proteome. Methods in Molecular Biology, Vol. 641. Humana Press. https://doi.org/10.1007/978-1-60761-711-2_1
3. Herold, G., et al. (2025). Internal Medicine. Herold Verlag 600
4. Kasper D L, Fauci A S, Hauser S L, Longo D L, Jameson J L, Loscalzo J et al. (2015) Harrison’s Principles of Internal Medicine. McGraw-Hill Education 289
5. Guideline (2021) Rational Laboratory Diagnostics for the Evaluation of Acute Kidney Injury and Progressive Kidney Disease. Interdisciplinary S2k Guideline. AWMF Registry No. 115/001
6. UroSurf by the University of Bern (2017) Leukocyte Cylinders. https://urosurf.elearning.aum.iml.unibe.ch/theory/sedicasts3.html?urosurf%7Ctheory%7Csediment%7Csedicasts%7C3