Re: F. Johannes P. van Valenberg, Andrew M. Hiar, Ellen Wallace, et al. Prospective Validation of an mRNA-based Urine Test for Surveillance of Patients with Bladder Cancer. Eur Urol. In press. https://doi.org/10.1016/j.eururo.2018.11.055 (European Urology)

We read with great interest the article by van Valenberg and colleagues [1]. In the first prospective multicenter study, the authors analyzed the diagnostic accuracy of the Xpert Bladder Cancer Monitor test in the surveillance of 239 patients previously diagnosed with non-muscle-invasive bladder cancer (NMIBC). In description, the authors confirmed sensitivity (SN) of 75% and negative predictive value (NPV) of 93% overall, and SN of 83% and NPV of 98% for high-grade (HG) tumors [1]. However, it is well known that cytology already has high sensitivity for HG tumors, but is limited by its low sensitivity for low-grade (LG) tumors [2].