Epithelial cells in urine can provide some information of diagnostic use, depending on the type of cells involved and the numbers present in the sample of urine. Usually, the information is most useful when paired with other findings from a urinalysis, along with the patient's report of symptoms. A typical urinalysis report will note if epithelial cells were found in the sample and will provide information about the type and numbers.
Epithelial cells are cells from the epithelium, the lining that covers the inside and outside of the body. They slough off routinely as new cells develop and old, dead ones flake away. Different areas of the body have distinct epithelial cells. Pathologists can see squamous, renal, and transitional epithelial cells in urine when they spin the urine to separate out the sediment.
Squamous epithelial cells are found along the genitals and on the outside of the body. Some usually show up in a urine sample because they are carried away by the stream of urine. Large numbers can be suggestive of contamination. The patient may not have carefully wiped before collecting a sample, allowing material from the outside of the body to enter the cup along with the urine sample.
Transitional epithelial cells in urine are also common. These cells line the urethra and bladder. In a person with an active inflammation, more cells may be shed as a result of irritation. Likewise, injuries can cause an increase in transitional epithelial cells. Paired with findings like blood in the urine and bacteria, they can be a sign of an infection.
Renal tubular epithelial cells are not a good sign. While a few may slip through, if they are present in large numbers, it is indicative of a problem with the kidneys. Other findings from the urinalysis can provide more information about what is happening in the kidneys and a doctor may also request a blood test to get an idea of how efficiently the kidneys are functioning.
If testing shows epithelial cells in urine, it is important to find out what kinds of cells are involved and in what concentrations. Minor numbers of epithelial cells in urine are generally not a cause for concern. If the numbers of squamous cells are high, a new urine sample may need to be taken to get a cleaner collection of urine for testing. Increased numbers of renal tubular cells call for additional testing to find out more about what is happening inside the patient.