Not all hematuria can be seen with the human eye. In fact, the most common type of hematuria—called microscopic hematuria—can only been seen by a health care expert under a microscope. In many cases, microscopic hematuria is spotted when a person has a urine test during a health exam. 

When a person can see the blood in his or her urine, the condition is called gross hematuria. People with gross hematuria have urine that is pink, red or brown.

“There’s a common misconception that if you see blood in your urine once and then it goes away that you’re in the clear,” says Angela B. Smith, MD, Assistant Professor of Urology at the University of North Carolina School of Medicine in Chapel Hill. “But it’s important to seek care the very first time you see blood in the urine, so your doctor can confirm that it’s there and refer you to a urologist for an evaluation.”

In most cases, people with either type of hematuria do not have pain or any other signs or symptoms. 

More serious causes are swelling of the kidney, urethra, bladder or prostate, or cancer of the kidney or bladder. Only a small percentage of people with microscopic hematuria have cancer. A history of smoking raises the risk of bladder or kidney cancer.

“In many cases, kidney cancer and bladder cancer do not cause physical symptoms, so the tumor may continue to grow without a person being aware of it,” says Michael J. Kennelly, MD, Professor in the Department of Surgery, Division of Urology at the Carolinas Medical Center – Charlotte in North Carolina. “By the time the tumor does cause symptoms, it may not be curable. That’s why it is so important to seek medical attention if you see blood in your urine. It could be a warning sign for a potentially life-threatening illness. Fortunately, the majority of the time, blood in the urine is not a sign of a serious illness.”

If your doctor thinks you may have hematuria, you will have a repeat urine test to make sure the first test was right. Your doctor will ask you about your health history, including infections, kidney stones, smoking, menstruation and recent injuries. He or she will also ask about medications you are taking.

Your doctor will perform a physical exam to check for pain or tenderness in the bladder or kidney area. Men may be given a digital rectal exam to look for prostate problems. Women may have a pelvic exam to look for the source of red blood cells in the urine.

Your doctor may order one more urine test to look for signs of infection, kidney disease and cancer. You may have a blood test to check for high levels of the protein creatinine, a sign of kidney disease.

In many cases, the doctor is not able to find out why there is blood in the urine, Dr. Smith notes. He or she may decide to retest your urine in a year. If blood is found, you may undergo more tests. Or you may be retested several years later. 

Hematuria is managed by treating its underlying cause. For example, if the condition is caused by a urinary tract infection, it is treated with antibiotics. Treatment for kidney stones can include waiting for the stone to pass by itself, medication or surgery.

If you are found to have kidney or bladder cancer, your doctor may refer you to an oncologist or urologic surgeon. If the tumor is found early, the cancer often can be cured. There are a number of options for kidney and bladder cancer treatment, including surgery, chemotherapy and radiation.

If the doctor rules out any medical problem causing hematuria, you will not need treatment.

“If you find blood in your urine, or your doctor tells you that you have microscopic hematuria, don’t panic,” Dr. Kennelly says. “The good news is that with proper evaluation, your doctor can find out the cause and if needed, make sure you get the correct treatment right away.”