From the Guidelines
The presence of rare transitional epithelial cells on a urinalysis is generally considered a normal finding and typically does not require any specific treatment or follow-up. Transitional epithelium lines the urinary tract from the renal pelvis to the proximal urethra, and it's normal for a few of these cells to shed and appear in urine samples. When the report indicates "rare" transitional cells, this reflects the normal turnover of the urinary tract lining. However, if transitional cells appear in large numbers or show atypical characteristics, further evaluation may be warranted as this could indicate inflammation, infection, or rarely, malignancy in the urinary tract. The significance increases if the patient has risk factors such as smoking history, chemical exposure, or symptoms like hematuria or dysuria. In such cases, additional testing might include repeat urinalysis, urine cytology, cystoscopy, or imaging studies, as recommended by guidelines such as those from the American Urological Association 1 and the National Comprehensive Cancer Network 1. For most patients with only rare transitional cells and no other concerning findings or symptoms, no intervention is needed as this represents normal physiology of the urinary tract epithelium's regular cellular turnover.
Some key points to consider in the evaluation of transitional epithelial cells in urinalysis include:
- The patient's overall clinical context, including risk factors for urinary tract malignancies or other diseases
- The presence of other abnormalities in the urinalysis, such as hematuria, proteinuria, or leukocyturia
- The need for follow-up testing, such as repeat urinalysis or more invasive procedures like cystoscopy, based on clinical judgment and guidelines
- The importance of considering the latest recommendations and classifications, such as those from the 2022 WHO Classification of Tumours: Urinary and Male Genital Tumours, as referenced in the NCCN Guidelines for Bladder Cancer 1.
In terms of specific recommendations for follow-up, the American Urological Association suggests that patients with a negative initial evaluation for asymptomatic microscopic hematuria should be considered for repeating urinalysis, voided urine cytology, and blood pressure determination at regular intervals, such as six, 12,24, and 36 months 1. However, the decision to perform further evaluation should be based on the individual patient's risk factors, symptoms, and clinical presentation. In general, for patients with only rare transitional epithelial cells and no other concerning findings, a conservative approach with no immediate intervention is appropriate, prioritizing morbidity, mortality, and quality of life outcomes.
From the Research
Rare Transitional Epithelial Cells on Urinalysis
- The presence of rare transitional epithelial cells on a urinalysis may not be a significant indicator of upper urinary tract infections (UTI) 2.
- According to a study published in 2020, transitional epithelial cells (TECs) do not seem to serve as a helpful marker for the diagnosis of upper UTI 2.
- In contrast, renal tubular epithelial cells (RTECs) have been found to add value in the diagnosis of upper urinary tract pathology, and may be helpful in discriminating between upper and lower UTIs 2.
- The stability of TECs and RTECs in urine has been evaluated, and they were found to be stable for at least 4 hours, depending on storage time, conditions, and urinary pH 2.
- The diagnostic performance of TECs was compared to RTECs, and RTECs demonstrated an acceptable diagnostic performance for the diagnosis of upper UTI, while TECs did not 2.