Diagnostic accuracy of urinary cytokeratin fragment-19 (CYFRA21-1) for bladder cancer

Bladder cancer (BC) is known for its high recurrence rate and requires constant patient monitoring. To confirm the diagnosis, a tissue sample from a cystoscopy is required, which the patient often avoids. Urine has the potential to be utilized as a diagnostic fluid because of its non-invasive nature and various biomarker contents. The aim of this study was to determine the diagnostic value of cytokeratin fragment-19 (CYFRA21-1) levels in urine for diagnosing BC. This single-center cross-sectional study included adults aged ≥18 years who presented with hematuria and had suspected BC based on imaging findings. Patients with a history of intravesical chemotherapy, radiotherapy and immunotherapy were excluded. Urine samples were collected prior to the cystoscopy. Detection of urinary CYFRA21-1 was carried out using the enzyme-linked immunosorbent assay (ELISA) method. Of 154 patients included in the study, the diagnosis of BC was confirmed in 92 patients. Patients with BC had significantly higher urinary CYFRA21-1 levels compared to the non-bladder cancer group. The sensitivity, specificity, positive and negative predictive value, and positive likelihood ratio of the CYFRA21-1 were 80.4%, 43.5%, 67.9%, 60% and 1.425, respectively. The area under the curve (AUC) for CYFRA21-1 was 0.608, computed from a receiver operating curve (ROC) with a cut-off value of 13.3 ng/mL. In conclusion, urinary CYFRA21-1 levels have moderate diagnostic accuracy in determining BC among suspected individuals. Due to its high sensitivity, this biomarker could potentially be used alongside other screening tools for BC detection.