Is red urine the same as hematuria?
Gross hematuria is the presence of red or brown urine. The degree of discoloration has limited value because as little as 1 mL of blood per liter of urine can cause visible discoloration.
In the initial evaluation of a patient with gross hematuria, it must be determined whether the urine discoloration is truly due to urinary tract bleeding.
This can be difficult for patients who are menstruating or postpartum. Conditions in which the urine may appear red, in the absence of bleeding, include use of rifampin, phenothiazine, or phenazopyridine (analgesic) and dietary ingestion of beets in predisposed individuals.
In these cases the urine dipstick will be negative for blood, and the microscopy will also not show any RBCs.
It is also important to differentiate hematuria from other causes of red urine, such as hemoglobinuria (following intravascular hemolysis) and myoglobinuria (following acute rhabdomyolysis).
In these cases the urine dipstick will be positive for blood, but the urine microscopy will not show many RBCs.
