Let's look at why this is so. The presence of red blood cells in urine is termed hematuria. Gross hematuria is a visible presence of blood in the urine. In addition, urine can contain breakdown products of red blood cells such as hemoglobin, appropriately enough called hemoglobinuria. Let's confine our thoughts to the causes of gross hematuria, and what type of diagnostic tests should be performed on these patients.
Gross hematuria can appear in several ways.
If enough red blood cells are present, the urine can be simply colored red throughout the urine stream. More commonly, blood will appear at the beginning or end of the urine stream. This distinction can be helpful to your veterinarian in beginning the diagnostic process. A word of caution, any evidence of hematuria is justification for a veterinary exam. Trauma is a common cause of hematuria.