Asymptomatic microscopic hematuria.(Disease/Disorder overview)

Asymptomatic microscopic hematuria--the presence of at least three to five red blood cells per high-power field on microscopy--has been estimated to occur in as much as 16% of the general population, although population-based studies vary widely.

Since it is asymptomatic, the condition is most often discovered on routine urinalysis.

Asymptomatic miscroscopic hematuria may be slightly more prevalent in women, because they are more likely to harbor a silent urinary tract infection.

The possible causes are wide ranging and include infection, cancer, urinary stones or crystals, kidney disorders, and drug-induced bleeding, as well as minor incidental causes that don't require treatment.

Although the incidence of significant urologic disease in patients with asymptomatic microscopic hematuria is low--probably only about 5%--the amount of blood in the urine doesn't correlate with the severity of any underlying disease.

Therefore, every patient who has microscopic hematuria should get a full work-up, with the hematuria considered to be serious until proven otherwise.

The finding of microscopic hematuria should prompt a complete history and physical that focus on the urinary tract and risk factors for urologic disease.