Defining hematuria

urine for lab test
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Blood in the urine

Medical Specialties: 

Internal medicine, Pediatrics, Urology, Family practice, Nephrology

Clinical Definition:

Hematuria, or blood in the urine, indicates that red blood cells are present. Even if you cannot see blood, you might have microscopic blood in your urine. Normally, the kidneys prevent blood from entering urine, but blood coming from the kidneys or other parts of the urinary tract (ureters, bladder, prostate, urethra) can end up in the urine.

In Our Own Words:

Hematuria is when blood is present in the urine. Hematuria can be frightening, but it is also common, affecting up to 21 percent of the population at some point. While hematuria is less often a sign of serious disease, visiting with a doctor about this problem is advised. Hematuria can happen in children or adults, and there are multiple potential causes, such as kidney infection, urinary stones, cancers of the urinary tract, enlarged prostate and many other conditions. Sometimes, no cause is found.

Clinical Evaluation of Hematuria:

Hematuria can be diagnosed using the following tests:

  • urinalysis
  • urine culture
  • urinary cytology (to identify the presence of cancerous cells)
  • urinary tract imaging (abdominal or pelvic CT)
  • cystoscopy (visualization of the urinary bladder or urethra using endoscopy--preferably performed during bleeding so as to identify the source of the bleed)
  • urinary dipstick to check for blood

    Potential Causes of Hematuria or "Red Urine"

    Here are some potential causes of hematuria:

    • neoplasms (cancer) of the kidney or ureters
    • polycystic disease
    • kidney stones
    • papillary necrosis
    • glomerulonephritis (inflammatory autoimmune diseases like Wegener granulomatosis, polyarteritis nodosa and lupus)
    • urinary tract infection
    • pyelonephritis (kidney infection)
    • embolus or thrombosis
    • malignant hypertension
    • ureter stricture
    • traumatic catheterization
    • benign prostatic hypertrophy (BPH)
    • prostatitis
    • prostate cancer
    • hemophilia
    • vigorous exercise (runner's hematuria)
    • sickle cell anemia
    • vaginal or rectal bleeding

    Of note, just because your urine is red, doesn't mean that there's blood in it, which is why a urine dipstick is performed to detect for actual blood. Here are some causes of (heme-negative) red urine:

    • medications (for example, laxatives, ibuprofen, and rifampin);
    • metabolites (for example, melanin, porphyrin and melanin);
    • natural or artificial food dyes (blackberries, food coloring, and beets).

    Treatment of Hematuria:

    Hematuria is a sign or symptom of disease. As such, in order to stop hematuria, whatever pathology is causing this bloody urine must be treated. For example, if the hematuria is due to a urinary tract infection, the urinary tract infection is treated with antibiotics.  

    Kidney stones, another common cause of hematuria, are treated with fluids, and, when a large stone blocks the flow of urine, a procedure called extracorporeal shock wave lithotripsy (ESWL) is commonly used to break up the stones.

    (More rarely, large kidney stones are treated with surgery.) 

    Cancerous causes of hematuria can be treated with chemotherapy or surgery.


    American Urological Association. Urology Care Foundation. "Blood in the Urine (Hematuria)." Jan. 2011. Accessed July 2013.

    American Academy of Pediatrics. Healthy Children.org. "Blood in Urine (Hematuria)." May 2013. Accessed July 2013.

    National Kidney Foundation. "Hematuria in Children." A to Z Health Guide 2013. Accessed July 2013.

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