Diagnostic Performance of GeneXpert BC as a Triage Test for Patients Presenting with Macroscopic Hematuria Suspicious for Urinary Bladder Cancer: A Multicenter Prospective Case-Control Study

Abstract

Background and objective

Our objective was to assess whether GeneXpert BC can be used as a triage test to exclude urinary bladder cancer (UBC) for patients with macroscopic hematuria.

Methods

We conducted a prospective study that include consecutive patients being evaluated for macroscopic hematuria between September 2020 and December 2022. Before cystoscopy, study participants provided a voided urine sample for GeneXpert BC analysis according to a case-control design with an emphasis on UBC detection. Descriptive statistics are reported for patient and tumor characteristics. To assess the diagnostic accuracy of the GeneXpert BC test, the sensitivity, specificity, and negative predictive value (NPV) were calculated, using the histopathologically proven UBC as the ground truth.

Key findings and limitations

In total, 1505 subjects presenting with macroscopic hematuria were enrolled in the study. After randomization and exclusions, GeneXpert BC testing was carried out for 312 participants. Of these, 151 patients from the case arm had UBC, 122 patients from the control arm (random 10%) were negative for UBC, and 39 patients from the case arm did not have malignancy. Using a predefined linear discriminant analysis (LDA) threshold of ≥0.22, the test had sensitivity of 0.94 (95% confidence interval [CI] 0.90–0.97), specificity of 0.52 (95% CI 0.42–0.59), and NPV of 0.99 (95% CI 0.98–0.99). All false-negative tumors were of low grade (Ta grade 1–2). Cystoscopy and computed tomography urography could have been omitted in 44% of the patients with macroscopic hematuria. At a secondary LDA threshold of ≥0.45, the test had sensitivity of 0.79 (95% CI 0.73–0.86), specificity of 0.83 (95% CI 0.76–0.89), and NPV of 0.97 (95% CI 0.96–0.98).

Conclusions and clinical implications

GeneXpert BC is a reliable triage test for deciding on whether further investigations are necessary in patients with macroscopic hematuria.

Patient summary

We assessed a test called GeneXpert BC for the detection of bladder cancer in patients with blood in their urine. GeneXpert BC performed well in ruling out bladder cancer for patients who did not have cancer according to further tests. Use of GeneXpert BC could help in avoiding scans and invasive tests for patients with a negative result.