Dipstick Urinalysis as a Test for Microhematuria and Occult Bladder Cancer

Introduction: There is a lack of evidence supporting the routine use of laboratory tests to detect bladder cancer. Identifying a cost-effective and widely available diagnostic aid may improve bladder cancer outcomes. We sought to evaluate the utility of dipstick urinalysis to detect microhematuria and diagnose bladder cancer in a large, diverse, contemporary cohort. Methods: All non-pregnant women and men 35 and older with a new diagnosis of microhematuria (≥3 RBC/hpf) were identified via a multi-center electronic medical record data warehouse query. Negative controls with no history of hematuria were randomly chosen and included to complete our cohort. Comparison between dipstick urinalysis and microscopic urinalysis on self-matched patients for the detection of microhematuria and diagnosis of bladder cancer was performed via Spearman's rank correlation coefficient, sensitivity/specificity testing, and ROC curve analysis. Results: A total of 46,842 patients were included. Spearman's rank order correlation (rho = 0.66) between degree of microhematuria on dipstick urinalysis and microscopic urinalysis indicated a strong positive relationship. The ROC curve for dipstick urinalysis to identify microhematuria had an AUC of 0.80 (95% CI 0.79-0.81). No difference (p = 0.83) in diagnostic accuracy between dipstick urinalysis (AUC 0.74, 95% CI 0.70-0.78) and microscopic urinalysis (AUC 0.73, 95% CI 0.69-0.78) as a test for bladder cancer was found. Conclusion: Dipstick urinalysis provides a highly specific test for microhematuria and similar accuracy to microscopic urinalysis when used as a diagnostic tool to detect bladder cancer.