Comparison of Automated Urinalysis Parameter Atyp.C and Urine Cytology for Detecting Bladder Carcinoma <i>In Situ</i>.

Background/Aim: (CIS) has not been specifically evaluated. Patients and Methods: We retrospectively analyzed patients with pathologically confirmed bladder CIS treated from January 2022 to July 2025. The diagnostic sensitivities of urine cytology and Atyp.C were compared, and the performance of their combination was assessed using exact McNemar tests and paired bootstrap analyses. Additional analyses were performed for pure CIS, primary bladder cancer, and recurrent bladder cancer. Results: This study included 61 patients. The overall sensitivity was 77% for urine cytology and 73.8% for Atyp.C, with only a small difference and bootstrap confidence intervals crossing zero. Combined testing showed a higher sensitivity (85.2%), but this increase was not statistically significant. Similar diagnostic performance and no significant incremental benefit were observed across the additional analyses. Conclusion: Atyp.C demonstrated diagnostic sensitivity comparable to urine cytology for the detection of bladder CIS. As an automated and cost-neutral parameter, Atyp.C may be a useful complementary indicator in routine clinical practice.