Microscopic (Non-visible) Hematuria

Abstract

Microscopic hematuria is detected during a urine dipstick or an examination of the urine sediment. It is conventionally defined as the presence of three or more red blood cells per high-power field in the sediment or at least “1+” of blood at urine dipstick. There is no reason not to believe that any disease causing a gross hematuria may instead present exclusively with a non-visible hematuria. Thus, a microscopic hematuria should, in principle, deserve the same attention of a gross hematuria. The problem arises when looking at the prevalence of an asymptomatic microscopic hematuria. This finding can be found in up to 20 % of the population and in up to 70 % of cases remains without explanation even after an accurate work-up. It is clear that not all patients with microscopic hematuria need to be investigated. The aim of this chapter is to help the GP in the selection of those patients with microscopic hematuria deserving a diagnostic work-up and to guide him through the choice of appropriate specialist referral.