Evaluation of asymptomatic microscopic hematuria.

Asymptomatic microscopic hematuria continues to be a common cause for urologic referral. Depending on the population under investigation, the condition is reported in 0.2% to 21.1% of subjects. Many possible etiologies exist for the presence of asymptomatic microscopic hematuria, ranging from insignificant lesions to potentially life-threatening lesions that may require urgent treatment. A cause for asymptomatic microscopic hematuria can be determined in 32% to 100% of patients undergoing a full urologic evaluation, with 3.4% to 56% of these patients having either moderately or highly significant lesions at the time of diagnosis. Consequently, full urologic evaluation is warranted in the majority of patients referred to a urologist with asymptomatic microscopic hematuria. In patients in whom no diagnosis is reached after initial evaluation, follow-up is necessary, although the extent and timing of such follow-up have not been adequately investigated. The ultimate goal of evaluating any patient with asymptomatic microscopic hematuria is the discovery of a significant lesion at an early stage when it is amenable to curative therapy and prior to that lesion causing significant morbidity. No randomized, prospective studies have compared the outcomes of patients with asymptomatic microscopic hematuria undergoing full evaluation with those of patients undergoing surveillance only. The data obtained in high-risk groups undergoing urinary dipstick screening for bladder cancer suggest that the bladder tumors discovered when evaluating all patients with asymptomatic microscopic hematuria may be more amenable to treatment than those normally encountered, thereby possibly reducing the mortality and morbidity associated with bladder cancer in these patients. These findings support the evaluation of patients with asymptomatic microscopic hematuria in a cost-conscious medical environment.