This document discusses hematuria, or the presence of red blood cells in urine. It defines hematuria and describes the varieties as microscopic or macroscopic/frank hematuria. Potential causes of hematuria are then outlined, including physiological, infectious, traumatic, inflammatory/autoimmune, stones, tumors, and drugs. Specific causes of hematuria in pregnancy are also listed. The document recommends consulting a nephrologist when hematuria is detected and outlines the clinical assessment and investigations that should be performed to determine the underlying cause.