From the Guidelines
The presence of epithelial cells in a urinalysis, particularly in large quantities, may indicate potential kidney issues, but small amounts are generally normal and can be considered contaminated if exceeding 10 WBCs and a significant number of epithelial cells are present 1. When evaluating the presence of epithelial cells in a urinalysis, it's essential to consider the type and quantity of cells.
- Normal urine may contain a few squamous epithelial cells from the urethra or external genitalia, which are shed during normal tissue turnover.
- However, increased numbers of epithelial cells, particularly renal tubular epithelial cells, may suggest kidney damage or inflammation, such as acute tubular necrosis, pyelonephritis, or nephrotoxicity from medications or toxins.
- The clinical significance of epithelial cells in a urinalysis depends on the patient's symptoms, medical history, and other urinalysis findings, such as protein, blood, or casts.
- A urine sample with more than 10 WBCs and a significant number of epithelial cells must be considered contaminated, and either an improved clean-catch method or catheterization must be tried, as stated in the clinical policy for children younger than three years presenting to the emergency department with fever 1.
- If a urinalysis shows elevated epithelial cells, especially renal tubular cells, additional testing may be needed, including repeat urinalysis, kidney function tests, or imaging studies.
- Isolated findings of epithelial cells without other abnormalities or symptoms often don't require treatment but should be monitored in follow-up testing.
From the Research
Presence of Epithelial Cells in Urinalysis
- The presence of epithelial cells in a urinalysis (UA) can indicate a potential issue with renal (kidney) health 2, 3.
- Renal epithelial cells play a crucial role in coordinating the innate immune response to infection, producing inflammatory mediators and antimicrobial proteins to aid in bacterial clearance 2.
- The presence of renal tubular epithelial cells (RTECs) in urine can be an indicator of upper urinary tract pathology, including infections and other conditions affecting the kidneys 3.
Diagnostic Value of Epithelial Cells
- RTECs have been shown to be a valuable diagnostic marker for upper urinary tract infections (UTIs), with acceptable diagnostic performance characteristics 3.
- In contrast, transitional epithelial cells (TECs) do not appear to be a helpful marker for UTIs 3.
- The presence of epithelial cells in urine can aid in the diagnosis of acute pyelonephritis, a bacterial infection of the kidney and renal pelvis 4.
Clinical Implications
- The detection of epithelial cells in urine can inform treatment decisions, such as the use of antibiotics and other therapies 2, 4.
- In cases of suspected upper UTI, the presence of RTECs can help guide diagnostic and therapeutic approaches 3.
- Patients with acute pyelonephritis may require hospital admission and parenteral antibiotic therapy, particularly if they are at risk of severe complications or have concurrent urinary tract obstruction 4.