Guide to Renal Epithelial Cells in Urine

WRITTEN BY

The Levels Team

Updated: 05/22/2025|12 min read

Summary

Renal epithelial cells are specialized cells that line the tiny tubules in the kidney, helping shuttle fluid and substances in and out of the kidneys. 

Why It Matters

Renal epithelial cells form the lining of the kidney's tubular system, which is responsible for filtering blood and producing urine. The tubules send essential substances back into the body and excrete waste products. These epithelial cells preserve the integrity of kidney tubules and help with important functions like maintaining fluid and electrolyte balance, regulating blood pressure, and eliminating waste products from the body.

In a healthy person, very few renal epithelial cells appear in urine. However, when kidney tissue becomes damaged or inflamed, these cells can detach from the tubular lining and be excreted in urine. Abnormal renal epithelial cell levels may be a sign of underlying kidney problems, such as kidney disease, infection, or inflammation.

In addition, certain medications can directly damage renal tubular cells, causing them to slough off into the urine. Heavy metal poisoning, such as from lead or mercury, can also cause tubular damage and lead to epithelial cells in the urine.

Associated Symptoms 

Renal epithelial cells in urine themselves are a laboratory finding rather than a medical condition. However, their presence may be associated with various kidney issues, each with its own symptoms.

Common symptoms that may indicate conditions associated with renal epithelial cells in urine (which can occur with urinary infections):

• Swelling: Puffiness around the eyes, ankles, or legs from fluid retention may be due to impaired kidney filtration
• Fatigue: Persistent tiredness, potentially resulting from waste product buildup or anemia related to kidney dysfunction
• Changes in urination: Increased frequency, decreased volume, or foamy appearance may be due to altered kidney function
• Flank pain: Discomfort in the mid-back region near the kidneys, potentially indicating inflammation or infection
• Nausea: Stomach discomfort may be related to waste product accumulation in the bloodstream
• High blood pressure: Elevated readings, potentially resulting from fluid retention and disrupted kidney regulation of blood pressure
• Decreased appetite: Reduced desire to eat can be associated with waste product buildup

It's important to note that early kidney issues may produce no noticeable symptoms despite causing renal epithelial cells to appear in urine. Additionally, the symptoms can vary widely depending on the underlying cause of tubular damage, such as infection, medication effects, or kidney disease. Regular urinalysis can help detect problems before symptoms develop or worsen.

Lifestyle Factors That Can Impact It

Activities that may impact renal epithelial cells in urine include:

• Hydration: Chronic dehydration can lead to concentrated urine and potentially exacerbate kidney damage, increasing the likelihood of renal epithelial cells appearing in urine.
• Smoking: Tobacco use restricts blood vessels, including those in the kidneys, potentially causing tubular damage
• Alcohol consumption: Heavy alcohol use can have direct toxic effects on kidney tubules, leading to renal epithelial cell shedding. 

Other Factors That Can Impact It

Genetic Conditions

• Alport syndrome: A genetic disorder affecting kidney filters, causing progressive kidney damage.
• Polycystic kidney disease: An inherited condition causing fluid-filled cysts to grow in the kidneys, and damage tubules.

Medical Conditions

• Acute kidney injury (AKI): A sudden decline in kidney function that causes extensive tubular damage.
• Urinary tract infections (UTIs): Bacterial infections can move into the kidneys, causing pyelonephritis and inflammation of renal tubules.
• Diabetes: Long-term kidney damage resulting from diabetes that affects all kidney structures including tubules.
• High blood pressure: Kidney damage caused by chronic high blood pressure can damage tubular structures.
• Glomerulonephritis: Inflammation of the kidney's filtering units can cause tubular damage.  

Medications and Supplements

• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Certain antibiotics
• Chemotherapy
• Contrast dyes

Individual Factors

• Age: Kidney function naturally declines with age, potentially increasing the risk of tubular damage.
• Obesity: Excess weight increases kidney workload.

Testing Accuracy and Stability

Microscopic examination of urine sediment for renal epithelial cells is somewhat subjective and requires skilled technicians for accurate identification. 

How It Relates to Other Markers

Other tests can provide insights about health status when viewed alongside renal epithelial cell results. These tests may include:

• Serum creatinine and BUN (blood urea nitrogen): Elevated levels can indicate decreased kidney function and help quantify the extent of damage.
• Urine protein-to-creatinine ratio: Measures protein excretion, which may increase with tubular damage.
• Kidney imaging (ultrasound, CT, MRI): Visualizes kidney structure to identify underlying causes of tubular damage.
• Kidney biopsy: Microscopic examination of kidney tissue provides definitive diagnosis of many kidney diseases.

How results could relate to other marker values:

• Renal epithelial cells + granular casts: May suggest acute tubular necrosis.
• Renal epithelial cells + white blood cells and bacteria: May suggest pyelonephritis (kidney infection).
• Renal epithelial cells + red blood cells and protein: May suggest glomerulonephritis.

Follow-up Considerations

If you have renal epithelial cells in your urine, your provider may make some of the following recommendations. You should always speak to your doctor if you have medical questions or before making medical decisions.

When Re-Testing May Be Appropriate

• After completing a course of medications known to be toxic to the kidneys
• 2-4 weeks following treatment for urinary tract infection or pyelonephritis
• Every 3-6 months for monitoring known kidney disease
• Following adjustment of medication dosages in patients with kidney dysfunction
• After acute illness that may have caused temporary kidney stress

Additional Testing Your Doctor May Consider

• 24-hour urine collection for protein, creatinine clearance, and electrolytes
• Genetic testing if hereditary kidney disease is suspected
• Autoimmune markers if glomerulonephritis is suspected
• Heavy metal screening if toxic exposure is possible
• Renal Doppler ultrasound to assess kidney blood flow

When Additional Care May Be Warranted

• Persistent or increasing numbers of renal epithelial cells despite intervention
• Symptoms like significant swelling, decreased urine output, or confusion
• Rapidly rising serum creatinine alongside renal epithelial cells in urine
• Appearance of renal epithelial cells with blood and protein in people with hypertension
• New onset of renal epithelial cells while taking medications known to cause kidney damage

Bibliography