Diseases & Conditions

Blood in the Urine

Overview, Causes, & Risk Factors

Blood in the urine can be visible, or it may only be noticed when the urine is tested.

What is going on in the body?

Not all cases of dark or red urine are due to blood in the urine. Muscle breakdown, eating a large amount of beets, or taking the antibiotic rifampin can all turn the urine dark or red. True blood in the urine can only be confirmed when red blood cells are seen in the urine with a microscope. There are many possible causes of blood in the urine.

What are the causes and risks of the condition?

There are many possible causes of blood in the urine, including:

  • benign prostatic hyperplasia, or an enlarged prostate, a common condition in men over age 40
  • bladder infections such as acute cystitis or recurrent cystitis
  • bleeding or blood-clotting disorders, such as hemophilia A or hemophilia B. Clotting problems may also be seen in a person who is taking too much of the blood-thinning drug warfarin.
  • infection in the urethra, known as urethritis. The urethra is the tube that carries urine from the bladder to the outside of the body.
  • kidney damage, such as from the condition called glomerulonephritis. In children, this damage is commonly due to an infection with Group A streptococcus, commonly known as a strep infection.
  • kidney infection, known as pyelonephritis
  • a kidney stone, which is usually quite painful
  • sickle cell disease, an inherited condition usually seen in African American people. It results in abnormally shaped red blood cells, which can damage the kidney.
  • a tumor or cancer, most commonly in the kidney, bladder, or prostate
  • Other causes are also possible. Sometimes, no cause can be found.

    Symptoms & Signs

    What are the signs and symptoms of the condition?

    Blood in the urine may or may not be noticed by the affected person. A person who has blood in the urine sometimes has other symptoms, including:

  • bleeding in other areas of the body
  • difficulty urinating
  • fever
  • pain, while urinating or not, in the genitals, lower abdomen, flank, or back
  • weight loss
  • These and all other symptoms should be reported to the doctor.

    Diagnosis & Tests

    How is the condition diagnosed?

    Diagnosis begins with a medical history and physical exam. This may be all that is needed to figure out the cause. In most cases, further testing is needed. Different tests may be ordered, depending on the suspected cause.

    Blood and urine tests are commonly performed. Special X-ray tests of the kidneys and bladder may also be done. A procedure called a cystoscopy may be needed in some cases. A tiny tube with a light and camera on the end is used. This tube can be inserted into the urethra and pushed up into the bladder. The inside of the urinary tract can be seen with the camera. This may help a doctor discover the source of bleeding.

    Prevention & Expectations

    What can be done to prevent the condition?

    Most cases cannot be prevented. Drinking a lot of fluids every day can help prevent kidney stones. Many cases of urethritis are caused by sexually transmitted diseases. So practicing safer sex could help prevent some cases of blood in the urine.

    What are the long-term effects of the condition?

    Long-term effects depend on the cause. Serious kidney infections or cancer may result in death. Many infections and kidney stones go away with treatment and have no long-term effects.

    What are the risks to others?

    Blood in the urine itself is not contagious. If an infection such as a sexually transmitted disease is the cause, the infection may be contagious.

    Treatment & Monitoring

    What are the treatments for the condition?

    Treatment is directed at the cause. A person who has a kidney stone is often given lots of fluid and pain medicines, and the stone usually passes on its own. If it doesn't, surgery or another procedure such as endoscopy may be needed to remove the stone. A person with an infection may be given antibiotics, while someone with a tumor or prostate enlargement may need surgery.

    What are the side effects of the treatments?

    Side effects depend on the treatments used. Antibiotics can cause an allergic reaction or stomach upset. Pain medicines may cause drowsiness or allergic reactions. Any surgery carries a risk of bleeding or infection.

    What happens after treatment for the condition?

    Treatment usually cures a person who has an infection or a kidney stone, and the person can resume normal activities. Someone with cancer may die if treatment is not successful. People with sickle cell disease often need fairly close monitoring and treatment for flare-ups of the disease throughout life.

    How is the condition monitored?

    Urine can be tested with a urinalysis and urine culture until blood is no longer seen. Other monitoring is related to the cause. For example, a person who takes warfarin often needs frequent prothrombin time, or PT, blood tests. Any new or worsening symptoms should be reported to the healthcare provider.


    Author:Adam Brochert, MD
    Date Written:
    Editor:Crist, Gayle P., MS, BA
    Edit Date:06/25/02
    Reviewer:Gail Hendrickson, RN, BS
    Date Reviewed:07/27/01


    Harrison's Principles of Internal Medicine, 1998, Fauci et al.