From the Guidelines
Finding transitional cells in urinalysis results is generally normal in small numbers but may indicate urinary tract inflammation or cancer when present in large quantities. Transitional cells normally line the urinary tract from the renal pelvis to the proximal urethra and are routinely shed into urine. When urinalysis shows elevated numbers of these cells, it warrants further investigation, particularly if they appear atypical or if the patient has risk factors like smoking or chemical exposure. The significance increases with age, as transitional cell carcinoma becomes more common in older adults. If large numbers or atypical transitional cells are found, a healthcare provider may recommend additional testing such as cystoscopy, imaging studies, or urine cytology, as suggested by the American Urological Association 1. The presence of these cells alone is not diagnostic but serves as a potential warning sign that should be evaluated in the context of other clinical findings and symptoms such as hematuria or urinary frequency. The shedding of transitional cells can increase due to inflammation, infection, instrumentation (like catheterization), or malignancy, which is why proper interpretation requires clinical correlation, as noted in recent guidelines on bladder cancer screening 1. Some key points to consider include:
- The American Urological Association recommends cystoscopy as a component of the initial office evaluation of microscopic hematuria in all adult patients more than 40 years of age and in patients less than 40 years of age with risk factors for bladder cancer 1.
- The US Preventive Services Task Force found inadequate evidence that screening for bladder cancer or treatment of screen-detected bladder cancer leads to improved disease-specific or overall morbidity or mortality 1.
- Recent studies have emphasized the importance of surveillance imaging following treatment for bladder cancer, highlighting the need for ongoing monitoring in patients with a history of bladder cancer 1. Given the potential for transitional cells to indicate underlying pathology, it is essential to approach these findings with a thorough evaluation, considering the patient's overall clinical context and risk factors, as supported by the most recent evidence 1.
From the Research
Significance of Transitional Cells in Urinalysis
- The presence of transitional cells in urinalysis can be an indicator of various conditions, including bladder cancer 2.
- Transitional cell carcinoma is a type of cancer that occurs in the lining of the bladder, and urinary cytology can be used to detect it 2.
- The diagnostic accuracy of urinary cytology for bladder cancer is relatively low, with a sensitivity of 13.3% in one study 3.
- However, the presence of transitional cells in urinalysis can still be a useful marker for bladder cancer, especially when combined with other diagnostic tests such as CT urography and flexible cystoscopy 4.
Diagnostic Strategies for Bladder Cancer
- A diagnostic strategy using CT urography and flexible cystoscopy as a triage test for rigid cystoscopy and follow-up can be effective in detecting bladder cancer 4.
- This strategy can reduce the number of flexible cystoscopies performed by 17% while maintaining high diagnostic accuracy 4.
- Voided urine cytology has a low sensitivity for detecting bladder cancer and may not be a useful diagnostic tool in a hospital haematuria rapid diagnosis clinic using CT urography and flexible cystoscopy 4.
Microsatellite Analysis for Bladder Cancer Diagnosis
- Microsatellite analysis of urine sediment can be a highly sensitive and specific marker for bladder cancer diagnosis, especially for low-stage and low-grade tumors 3.
- This method can detect allelic abnormalities in the DNA extracted from urine sediment, which can be indicative of bladder cancer 3.
- Microsatellite analysis may be a useful diagnostic tool for bladder cancer, particularly in patients with negative or equivocal urinary cytology results 3.