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Blood in Urine
(Hematuria)

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Medical Author:

Gary D. Steinberg, MD

Medical Author:

G. Joel DeCastro, MD

Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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What is blood in urine (hematuria)?

Hematuria, or blood in the urine, can be either gross (visible) or microscopic (as defined by more than three to five red blood cells per high power field when viewed under magnification). Gross hematuria can vary widely in appearance, from light pink to deep red with clots. Despite the quantity of blood in the urine being different, the types of conditions that can cause the problem are the same, and the workup or evaluation that is needed is identical.

People with gross hematuria usually present to their doctor with this as a primary complaint. Microscopic hematuria, on the other hand, is most commonly detected as part of a periodic checkup by a primary-care physician.

What are the causes of blood in urine?

The causes of gross and microscopic hematuria are similar and may result from bleeding anywhere along the urinary tract. One cannot readily distinguish between blood originating in the kidneys, ureters (the tubes that transport urine from the kidneys to the bladder), bladder, or urethra. Any degree of blood in the urine should be fully evaluated by a physician, even if it resolves spontaneously.

Infection of the urine, stemming either from the kidneys or bladder, is a common cause of microscopic hematuria. Kidney and bladder stones can cause irritation and abrasion of the urinary tract, leading to microscopic or gross hematuria. Trauma affecting any of the components of the urinary tract or the prostate can lead to bloody urine. Hematuria can also be associated with renal (or kidney) disease, as well as hematologic disorders involving the body's clotting system. Medications that increase the risk of bleeding, such as aspirin, warfarin (Coumadin), or clopidogrel (Plavix), may also lead to bloody urine. Lastly, cancer anywhere along the urinary tract can present with hematuria.