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BLOOD IN THE URINE OVERVIEW — Hematuria is the medical term for red blood cells in the urine. Red blood cells in the urine can come from the kidney (where urine is made) or anywhere in the urinary tract (figure 1). The urinary tract includes the ureters (the tubes that carry the urine from the kidneys to the bladder), the bladder (where urine is stored), the prostate (in men), and the urethra (the tube through which urine exits the body).
Although seeing blood in the urine can be frightening, most of the time hematuria is not life threatening. However, it is important to investigate the cause of hematuria because, occasionally, it is caused by a serious condition.
This article will review the potential causes, evaluation, and treatment of blood in the urine in adults. Blood in the urine in children is discussed separately (see "Patient education: Blood in the urine (hematuria) in children (Beyond the Basics)"). More detailed information is available by subscription. (See "Etiology and evaluation of hematuria in adults".)
TYPES OF HEMATURIA — There are two main types of hematuria: gross and microscopic.
●Gross hematuria – Gross hematuria means that you can see blood with the naked eye because the urine is pink, red, purplish-red, brownish-red, or tea-colored. If you see blood in your urine, you should call your healthcare provider.
●Microscopic hematuria – Microscopic hematuria means that the urine is normal in color, but there are an increased number of red blood cells seen with a microscope. It is usually discovered when a urine sample is tested with a dipstick by a health care provider. The results of a dipstick test are not always accurate and should be confirmed with a microscopic examination.
CAUSES OF BLOOD IN THE URINE — A number of conditions can cause hematuria.
●Bladder infection (also called acute cystitis), which typically causes burning or pain with urination (see "Patient education: Urinary tract infections in adolescents and adults (Beyond the Basics)")
●Kidney infection (also called pyelonephritis) (see "Patient education: Urinary tract infections in adolescents and adults (Beyond the Basics)")
●Kidney stones, which usually present with one-sided back or flank pain that can be severe (see "Patient education: Kidney stones in adults (Beyond the Basics)")
●Certain kidney diseases
●Vigorous exercise or injury (for example, after falling off a bike and bruising a kidney)
●Enlargement of the prostate (called benign prostatic hyperplasia), which is a common problem in older men
●Cancer of the bladder, prostate, or kidney, more often in patients over age 50 years (see "Patient education: Bladder cancer diagnosis and staging (Beyond the Basics)")
Sometimes, the urine appears to have blood in it because there are other red substances (pigments) in the urine. This can happen if you eat an excessive amount of beets (called beeturia), food dyes, or certain medications (such as phenazopyridine/Pyridium).
TESTS — There are a number of tests available to determine the cause of hematuria. Most people do not need every single test.
●Urine tests – Urine tests can provide clues about the cause of hematuria. This may include a urinalysis, which is performed with a dipstick test and sometimes uses a microscope to analyze the contents of the urine. Another test that may be performed is a urine cytology, which uses a microscope to analyze cells from the lining of the bladder and kidney (found in the urine).
●Blood tests – Blood tests may be used to look for evidence of kidney or other diseases that can cause hematuria.
●CT scan – Computed tomography, or CT scan, is a radiologic test that examines the structure of the kidneys, ureters, and bladder. Kidney stones or abnormalities of the kidneys, ureters, and bladder can usually be seen with a CT scan. A dye is usually injected into a vein during the test, which highlights any possible abnormalities.
●Kidney ultrasound – An ultrasound of the kidney is an alternative to CT scan and is preferred for people who are allergic to the dye used in CT. Ultrasound uses sound waves to create a picture of the kidney's structure.
●Cystoscopy – Cystoscopy is a procedure that is most often done in an office setting but sometimes is done as a day surgery procedure. A small tube with a camera is inserted into the bladder through the urethra (figure 1). A numbing gel is applied before the tube is inserted to decrease discomfort. The vast majority of patients tolerate this 5 to 10 minute procedure very well.
During cystoscopy, the clinician examines the lining of the bladder to determine whether there are any abnormalities. If abnormal tissue is seen, a biopsy can be taken. The biopsy is examined with a microscope to determine whether abnormal or cancerous cells are present.
●Kidney biopsy – During a kidney (renal) biopsy, a clinician removes a small piece of tissue from the kidney; the tissue is later examined with a microscope for signs of kidney disease. A full description of renal biopsy is available separately. (See "Patient education: Kidney (renal) biopsy (Beyond the Basics)".)
TREATMENT OF BLOOD IN THE URINE — There is no one specific treatment for all cases of hematuria. Rather, treatment is aimed at the specific underlying cause, if a cause can be determined. (See "Patient education: Urinary tract infections in adolescents and adults (Beyond the Basics)" and "Patient education: Kidney stones in adults (Beyond the Basics)" and "Patient education: Glomerular disease (Beyond the Basics)" and "Patient education: Chronic kidney disease (Beyond the Basics)".)
Follow-up testing — If no underlying cause for hematuria is found during the initial evaluation, follow-up urine testing and blood pressure monitoring may be recommended every three to six months.
This is especially true if you are at increased risk for bladder cancer. A number of factors can increase your risk of bladder cancer, including being older than 50 years, smoking cigarettes and other tobacco products, and exposure to certain industrial chemicals. (See "Patient education: Bladder cancer diagnosis and staging (Beyond the Basics)".)
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient education: Bladder cancer (The Basics)
Patient education: Blood in the urine (hematuria) in adults (The Basics)
Patient education: Kidney cancer (The Basics)
Patient education: Rhabdomyolysis (The Basics)
Patient education: Disseminated intravascular coagulation (The Basics)
Patient education: Glomerular disease (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient education: Kidney stones in adults (Beyond the Basics)
Patient education: Blood in the urine (hematuria) in children (Beyond the Basics)
Patient education: Urinary tract infections in adolescents and adults (Beyond the Basics)
Patient education: Bladder cancer diagnosis and staging (Beyond the Basics)
Patient education: Kidney (renal) biopsy (Beyond the Basics)
Patient education: Glomerular disease (Beyond the Basics)
Patient education: Chronic kidney disease (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Acute simple cystitis in adult males
Acute simple cystitis in females
Etiology and evaluation of hematuria in adults
Isolated and persistent glomerular hematuria in adults
The kidney biopsy
Loin pain-hematuria syndrome
Thin basement membrane nephropathy (benign familial hematuria)
Urinalysis in the diagnosis of kidney disease
Acute complicated urinary tract infection (including pyelonephritis) in adults
The following organizations also provide reliable health information.
●National Library of Medicine
●National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
●National Kidney Foundation
ACKNOWLEDGMENT — The editorial staff at UpToDate would like to acknowledge Adam S Feldman, MD, MPH, who contributed to an earlier version of this topic review.
1 : A prospective analysis of 1,930 patients with hematuria to evaluate current diagnostic practice.
3 : Diagnosis, evaluation and follow-up of asymptomatic microhematuria (AMH) in adults: AUA guideline.