Audit of cytology of upper urinary tract

Cytology is an essential tool for the investigation of urinary tract malignancy. In this audit, we aimed to assess our laboratory performance in the diagnosis of upper urinary tract malignancy and to use the information provided to improve our service.

We retrieved cytology reports of upper urinary tract specimens from two periods, re-evaluated the cases, compared the reports with histology data and estimated the sensitivity, specificity and positive predictive value (PPV). In the time interval between the two periods, we adopted new terminology, established better communication with clinicians and gained experience in the field. Finally, the data from the two periods were compared.

In phase A, we estimated a sensitivity of 73%, specificity of 86% and PPV of 84.6%. As a result of the cytological re-evaluation, correlation with histology and clinical follow-up, plus communication with the clinicians during the audit, we established new terminology and a new request form. A three tiered grading system of atypia (mild, moderate and severe) was replaced by a two tiered grading system. The first category "atypia probably benign" corresponded to "mild atypia" while the second category "atypia, not otherwise specified" corresponded to "moderate atypia". The cases diagnosed as "severe atypia" were reclassified as "suspicious for malignancy". In phase B, the sensitivity, specificity and PPV were 75%, 89% and 90%, respectively.

Our laboratory performance is in concordance with reported data and has been improved through this study. The audit process is extremely valuable for the identification of problems, for taking action and, finally, for the improvement of the clinical cytology service in the field of upper urinary tract malignancy.