Evaluation of Hematuria

www.turner-white.com B lood in the urine is a common problem that can be a sign of a number of benign and malignant underlying diseases. Hematuria may be macroscopic (visible on gross examination) or microscopic.1,2 The American Urological Association defines microscopic hematuria as 3 or more red blood cells (RBCs) per high-power field (hpf) on microscopic analysis of 2 or 3 properly collected urine specimens,3 although other definitions range from 1 to more than 10 RBCs/hpf.2,4,5 The causes of hematuria can be broadly categorized into renal and extrarenal, and renal causes can be subdivided into glomerular and nonglomerular (Table 1). A detailed history is essential in elucidating the cause of hematuria, and a family history should not be overlooked. Laboratory evaluation is also important as microscopic examination of the urine can confirm whether blood is actually present in the urine (eg, in the case of a false-positive dipstick test) and may help determine whether the source of blood is glomerular or nonglomerular.6 Further investigation with imaging studies may be warranted in some disease processes. This article discusses the approach to the patient with hematuria, with an emphasis on history and laboratory evaluation.