Hematuria is blood in the urine. Two types of blood in the urine exist. Blood that can be seen in the urine is called gross hematuria. Blood that cannot be seen in the urine, except when examined with a microscope, is called microscopic hematuria.

What are the symptoms of hematuria?
Most people with microscopic hematuria do not have symptoms. People with gross hematuria have urine that is pink, red, or cola-colored due to the presence of red blood cells (RBCs). Even a small amount of blood in the urine can cause urine to change color. In most cases, people with gross hematuria do not have other symptoms. However, people with gross hematuria that includes blood clots in the urine may have pain.

What is the urinary tract?
The urinary tract is the body’s drainage system for removing wastes and extra water. The urinary tract includes two kidneys, two ureters, a bladder, and a urethra. The kidneys are two bean-shaped organs, each about the size of a fist. They are located near the middle of the back, just below the rib cage, one on each side of the spine. Every day, the two kidneys process about 200 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra water. The urine flows from the kidneys to the bladder through tubes called ureters. The bladder stores urine until releasing it through urination. When the bladder empties, urine flows out of the body through a tube called the urethra at the bottom of the bladder.

What causes hematuria?
Hematuria can be caused by menstruation, vigorous exercise, sexual activity, viral illness, trauma, or infection, such as a urinary tract infection (UTI). More serious causes of hematuria include
-- cancer of the kidney or bladder
-- inflammation of the kidney, urethra, bladder, or prostate-a walnut-shaped gland in men that surrounds the urethra at the neck of the bladder and supplies fluid that goes into semen
-- Polycystic Kidney Disease-an inherited disorder characterized by many grape-like clusters of fluid-filled cysts that make both kidneys larger over time, taking over and destroying working kidney tissue
-- blood clots
-- blood clotting disorders, such as hemophilia
-- sickle cell disease-an inherited disorder in which RBCs form an abnormal crescent shape, resulting in less oxygen delivered to the body’s tissues, clogging of small blood vessels, and disruption of healthy blood flow

Who is at risk for hematuria?
Almost anyone, including children and teens, can have hematuria. Factors that increase the chance a person will have hematuria include
-- a family history of kidney disease
-- an enlarged prostate, which typically occurs in men age 50 or older
-- urinary stone disease
-- certain medications including aspirin and other pain relievers, blood thinners, and antibiotics
-- strenuous exercise such as long-distance running
-- a recent bacterial or viral infection