Evaluation of asymptomatic microhematuria

The purpose of this study was to evaluate a comprehensive urine cytodiagnostic assay to assist in localizing the site of origin and the etiology of asymptomatic microhematuria. This analysis, which assesses various qualitative and quantitative aspects of the voided urine, is compared simultaneously with controls obtained from the established routine urologic evaluation.

One hundred consecutive subjects who presented solely for the evaluation of asymptomatic microhematuria were evaluated by the established routine urologic evaluation and a refined urine cytodiagnostic assay. For the purpose of this study, only calculi and neoplasms were considered significant findings.

The incidence of significant urologic disease was 13% (3 renal neoplasms, 2 urothelial bladder carcinomas, and 8 urinary calculi). The refined urine cytodiagnostic assay identified both uroepithelial vesical neoplasms, 7 of the 8 urinary calculi, and none of the 3 renal neoplasms. The presence of dysmorphic urinary red blood cells (RBCs) and RBC casts was strongly suggestive of renal parenchymal bleeding. Overall, 43 of 44 subjects (98%) with dysmorphic RBCs and RBC casts failed to demonstrate any significant urologic etiology.

These preliminary results suggest that the refined cytodiagnostic urine assay may be helpful in distinguishing whether a given patient's microhematuria is of a significant urologic or a renal parenchymal cause. The addition of this specialized urinalysis may prove a useful adjunct in improving the diagnostic yield in patients with asymptomatic microhematuria.