Hematuria is the presence of red blood cells in an individual's urine and can be categorized in two different ways. Microscopic hematuria is the term used to describe blood cells in the urine that cannot be seen with the naked eye but can be seen through a microscope. Gross hematuria describes blood that can be seen in the urine with the naked eye. When an individual is affected by gross hematuria, their urine appears brown, red, or pink. It takes a nominal amount of blood to change the color of urine. Depending on its cause, other symptoms may or may not manifest in individuals affected by hematuria. Hematuria has many possible causes. Several diagnostic methods may be used to identify the underlying cause of hematuria, including a urinalysis, blood testing, CT scan, cystoscopy, kidney biopsy, and MRIs.
Urinary Tract Infection
An individual affected by a urinary tract infection may experience blood in their urine. The urinary tract consists of the kidneys; bladder; ureters, which are tubes that carry urine from the kidneys to the bladder; and urethra, the tube from the bladder to the outside of the body. Urinary tract infections are when any part of the urinary tract becomes infected by a harmful pathogen. Most urinary tract infections occur in an affected individual's bladder where urine is stored until it is ready to be emptied. Bacteria enter the body through the urethra and colonize in the bladder, and left untreated they can mobilize up the ureters and into the kidneys. Hematuria occurs when the infection causing pathogen damages the bladder walls, ureter walls, or tissues in the kidneys. The small vessels that supply these tissues become damaged as well, causing red blood cells to leak into the individual's urine stream. Most urinary tract infections begin with microscopic hematuria and will progress to gross hematuria without medical intervention.