What does it mean if routine urine test shows occult blood?

The presence of occult blood in a routine urine test may be caused by various factors. It could result from urinary tract infections such as cystitis or pyelonephritis, in which inflammation leads to congestion, edema, and erosion of the urothelium, increasing the number of red blood cells in the urine. Urinary stones or tumors may also cause local mucosal damage, leading to elevated red blood cells in the urine. In addition, trauma to the waist or lower abdomen may result in tissue contusion of the urinary system and allow red blood cells to enter the urine. For cases of occult blood detected in routine urinalysis, further physical examination, laboratory tests, and imaging studies are recommended to determine the underlying cause and guide appropriate treatment.