How to know if blood in urine is serious?

Blood in your urine is one of those symptoms that immediately demands attention, yet many people hesitate to seek help. In some cases, blood in urine (medically called hematuria) stems from benign causes like strenuous exercise or certain medications. In other cases, it signals bladder cancer, kidney disease, or urinary tract infections requiring prompt treatment.

At St. Pete Urology, we evaluate hundreds of patients with hematuria each year. Based on current American Urological Association guidelines and decades of combined clinical experience from our board-certified urologists, this guide explains exactly when blood in urine demands immediate medical attention and when it might resolve on its own.

Understanding Blood in Urine (Hematuria)

Hematuria refers to the presence of red blood cells in urine. Medical professionals classify it into two distinct types. Gross hematuria appears visible to the naked eye, turning urine pink, red, or tea-colored. Microscopic hematuria contains blood cells detectable only through laboratory testing, with no visible color change.

Over 20% of patients who see urologists receive a hematuria diagnosis, according to Cleveland Clinic research. Microscopic hematuria affects approximately 2% to 31% of the general population. While these numbers might sound alarming, many cases stem from temporary, harmless conditions. The challenge lies in distinguishing benign causes from serious underlying diseases.

The kidneys filter waste from blood to produce urine, which then travels through ureters to the bladder before exiting through the urethra. Blood can enter urine at any point along this urinary tract. Sometimes blood originates from the kidneys themselves due to disease or injury. Other times, bleeding occurs in the bladder, ureters, or urethra. Location matters because it helps urologists determine the underlying cause and appropriate treatment approach.

Common Causes of Blood in Urine

Blood in urine stems from numerous conditions ranging from completely benign to life-threatening. According to the National Institute of Diabetes and Digestive and Kidney Diseases, the most common causes include urinary tract infections, kidney stones, enlarged prostate, kidney disease, cancer, inherited disorders, and certain medications.

Benign causes often resolve without treatment. Vigorous exercise, particularly running, can temporarily produce microscopic hematuria that disappears within 24 to 48 hours. Certain foods like beets, rhubarb, and blackberries contain pigments that turn urine reddish, mimicking blood. Blood-thinning medications including aspirin, warfarin, and clopidogrel increase bleeding risk throughout the body, including the urinary tract.

Urinary tract infections represent one of the most frequent causes of visible blood in urine. Bacteria invading the bladder or kidneys cause inflammation, leading to bleeding. UTIs typically produce additional symptoms: burning during urination, frequent urination, urgency, cloudy or foul-smelling urine, and lower abdominal pain. Women experience UTIs more frequently than men due to shorter urethral length.

Kidney stones cause bleeding as they move through the urinary tract. These hard mineral deposits scratch the delicate lining of ureters and bladder, producing both blood and intense pain. Stone-related hematuria often accompanies severe flank pain, nausea, vomiting, and difficulty urinating. Stones affect approximately 10% of Americans at some point during their lives.

Enlarged prostate, medically termed benign prostatic hyperplasia (BPH), commonly affects men over 50. As the prostate enlarges, it compresses the urethra and can cause bleeding. BPH-related hematuria usually presents with other urinary symptoms: weak urine stream, difficulty starting urination, frequent nighttime urination, and incomplete bladder emptying.

Serious causes require immediate evaluation and treatment. Bladder cancer produces painless hematuria in approximately 80% of cases. The American Cancer Society estimates 82,290 new bladder cancer diagnoses in 2023, with men facing higher risk than women. Johns Hopkins Medicine reports that cancer accounts for 10% to 20% of gross hematuria cases in patients over 40.

Kidney disease, including glomerulonephritis and polycystic kidney disease, damages kidney filters and allows blood to leak into urine. These conditions often progress slowly without obvious symptoms until significant kidney damage occurs. Early detection through urine testing proves crucial for preventing kidney failure.

When Blood in Urine Requires Immediate Medical Attention

Most hematuria cases warrant medical evaluation within days rather than hours. However, certain situations demand immediate emergency department care. Seek emergency treatment if you pass large blood clots, experience complete inability to urinate, develop severe abdominal or back pain alongside bloody urine, notice blood in urine accompanied by fever and chills, or have a history of kidney disease with sudden hematuria.

Blood clots in urine indicate significant bleeding that could lead to urinary blockage. Clots form when bleeding exceeds the body’s natural anticoagulant mechanisms in urine. Large clots can obstruct the urethra or ureters, creating a medical emergency requiring catheter placement and continuous bladder irrigation.

According to Mayo Clinic, painless gross hematuria in adults over 35 requires prompt urologic evaluation because it represents the most common presentation of bladder cancer. Don’t assume blood in urine is harmless just because you feel fine otherwise. Many serious urological conditions produce no symptoms beyond hematuria in their early stages.

Certain risk factors elevate concern when hematuria appears. Age over 35, smoking history, occupational exposure to chemicals (particularly in the dye, rubber, or leather industries), history of pelvic radiation, chronic bladder infections, long-term catheter use, and family history of kidney disease or bladder cancer all increase the likelihood of serious underlying disease.

Men should note that blood in urine combined with difficulty urinating or weak urine stream could indicate prostate problems or urethral strictures. Women experiencing hematuria during menstruation need repeat testing after their period ends to confirm whether blood truly originates from the urinary tract.

Diagnostic Tests and What to Expect

When you visit a urologist for hematuria evaluation, expect a comprehensive assessment starting with detailed medical history and physical examination. Your doctor will ask about medications, recent illnesses, family history, occupational exposures, and associated symptoms. The physical exam may include abdominal palpation, percussion for kidney tenderness, and digital rectal exam in men or pelvic exam in women.

Urinalysis serves as the foundation of hematuria diagnosis. This simple test examines urine under a microscope to confirm the presence of red blood cells and identify other abnormalities like proteins, bacteria, or crystals. Labs report results as red blood cells per high-power field, with more than three red blood cells per high-power field confirming hematuria.

Blood tests measure kidney function by checking creatinine and blood urea nitrogen levels. Elevated levels suggest kidney disease. Additional blood tests may screen for clotting disorders, inflammatory markers, or prostate-specific antigen (PSA) in men.

Imaging studies visualize the entire urinary tract. Computed tomography (CT) urogram combines CT scanning with contrast dye injection to create detailed images of kidneys, ureters, and bladder. This test excels at detecting stones, tumors, and structural abnormalities. Ultrasound uses sound waves to examine kidneys and bladder without radiation exposure, making it ideal for pregnant women and children. Magnetic resonance imaging (MRI) urogram serves as an alternative when CT scans pose risks.

Cystoscopy allows direct visualization of the bladder’s interior. During this procedure, performed at St. Pete Urology’s office, your urologist passes a thin, flexible tube with a camera through the urethra into the bladder. Local anesthesia minimizes discomfort. Cystoscopy identifies bladder tumors, stones, inflammation, and other abnormalities invisible on imaging tests. Your doctor may collect tissue samples (biopsies) during cystoscopy if suspicious areas appear.

The 2020 American Urological Association guidelines recommend risk-stratified evaluation based on factors including age, smoking history, and degree of hematuria. Low-risk patients might need only urinalysis and imaging. High-risk patients require comprehensive evaluation including cystoscopy. Dr. Nicholas Laryngakis, Dr. Reid Graves, Dr. Adam Oppenheim, and Dr. Ankur Shah at St. Pete Urology follow these evidence-based protocols to ensure appropriate, cost-effective diagnosis.

Treatment Options Based on Underlying Causes

Hematuria treatment targets the underlying cause rather than the blood itself. Urinary tract infections respond to antibiotics selected based on urine culture results. Most uncomplicated UTIs clear within three to seven days. Recurrent UTIs may require longer antibiotic courses, preventive antibiotics, or further investigation into structural abnormalities.

Small kidney stones often pass spontaneously with increased fluid intake and pain medication. Medical expulsive therapy using medications like tamsulosin relaxes ureter muscles, facilitating stone passage. Larger stones require intervention. Extracorporeal shock wave lithotripsy (ESWL) uses sound waves to fragment stones. Ureteroscopy involves passing a thin scope through the urethra and bladder into the ureter to remove or destroy stones with laser energy. Percutaneous nephrolithotomy treats very large kidney stones through a small back incision.

Enlarged prostate treatment depends on symptom severity. Medications including alpha-blockers (tamsulosin, alfuzosin) and 5-alpha reductase inhibitors (finasteride, dutasteride) shrink the prostate and improve urine flow. Minimally invasive procedures like UroLift, Rezum water vapor therapy, and GreenLight laser vaporization provide symptom relief without major surgery. Transurethral resection of the prostate (TURP) remains the gold standard surgical treatment for severe BPH.

Bladder cancer treatment varies by stage and grade. Non-muscle-invasive bladder cancer responds to transurethral resection followed by intravesical therapy (chemotherapy or immunotherapy instilled directly into the bladder). Muscle-invasive bladder cancer typically requires radical cystectomy with urinary reconstruction or combination therapy including chemotherapy and radiation. Our team at St. Pete Urology specializes in minimally invasive robotic surgery for bladder cancer, offering faster recovery and fewer complications than traditional open surgery.

Kidney disease management focuses on preserving remaining kidney function. Treatment includes blood pressure control, protein restriction, medications to reduce proteinuria, and addressing underlying causes like autoimmune diseases. Advanced kidney disease may eventually require dialysis or kidney transplantation.

Some hematuria cases resolve without identifying a specific cause. Your urologist may recommend observation with periodic follow-up testing if initial evaluation reveals no serious abnormality. Checking for changes in urine color can help monitor your condition between appointments. Most experts recommend follow-up urinalysis every three to six months for one year, followed by annual testing if hematuria persists.

Prevention and When to Contact a Urologist

While not all causes of hematuria are preventable, several strategies reduce your risk. Stay well-hydrated by drinking eight to ten glasses of water daily. Adequate hydration dilutes urine, reduces stone formation, and flushes bacteria from the urinary tract. Limit salt intake to decrease calcium excretion in urine, lowering stone risk.

Quit smoking to dramatically reduce bladder cancer risk. Smokers face four to seven times higher bladder cancer rates than non-smokers. The good news is that bladder cancer risk decreases progressively after smoking cessation, approaching that of never-smokers after 15 to 20 years.

Practice good bathroom hygiene to prevent urinary tract infections. Women should wipe front to back, urinate after sexual activity, and avoid prolonged bladder distention. Men with enlarged prostate should avoid prolonged sitting, limit caffeine and alcohol, and maintain healthy weight.

Use protective equipment when working with chemicals known to increase bladder cancer risk, including benzene, aromatic amines, and certain industrial dyes. Follow workplace safety protocols and report any exposure to your healthcare provider.

Contact a urologist promptly if you notice blood in your urine, even if it appears only once. Many serious conditions produce intermittent hematuria. A small bladder tumor might bleed once, stop, then bleed again months later. Delaying evaluation allows cancers and other diseases to progress.

Schedule an appointment within days (not weeks) if you’re over 35, have a smoking history, work with chemicals, or have a family history of urological cancer. Same-day or next-day evaluation makes sense when hematuria accompanies pain, difficulty urinating, or fever.

At St. Pete Urology, our board-certified urologists use the latest diagnostic technology and evidence-based treatment protocols to evaluate hematuria thoroughly and efficiently. Located at 830 Central Ave, Suite 100, St. Petersburg, FL 33701, we serve patients throughout the Tampa Bay area including St. Petersburg, Clearwater, Pinellas Park, and surrounding communities.

Conclusion

Blood in urine demands medical evaluation regardless of whether you can see it or whether it causes other symptoms. While many cases stem from benign causes like infections or kidney stones, hematuria can also signal bladder cancer, kidney disease, or other serious conditions requiring prompt treatment.

The key determinants of seriousness include your age, risk factors, associated symptoms, and whether hematuria is gross or microscopic. Anyone over 35 with visible blood in urine should see a urologist within days. Younger patients or those with microscopic hematuria discovered incidentally need evaluation within weeks.

Don’t ignore hematuria hoping it will resolve on its own. Early diagnosis of bladder cancer, kidney disease, and other urological conditions dramatically improves treatment success and long-term outcomes. A thorough evaluation by a board-certified urologist provides definitive answers and peace of mind.

If you’ve noticed blood in your urine, contact St. Pete Urology at (727) 478-1172 to schedule an appointment with Dr. Graves, Dr. Laryngakis, Dr. Oppenheim, or Dr. Shah. Our team combines advanced diagnostic capabilities with compassionate, personalized care to identify the cause of your hematuria and develop an effective treatment plan tailored to your needs.

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References

• American Cancer Society. (2023). Key statistics for bladder cancer. https://www.cancer.org/cancer/bladder-cancer/about/key-statistics.html
• Barocas, D. A., Lotan, Y., Matulewicz, R. S., Raman, J. D., Westerman, M. E., Kirkby, E., Pak, L. J., & Souter, L. (2025). Updates to microhematuria: AUA/SUFU guideline. Journal of Urology, 213(5), 547-557. https://doi.org/10.1097/JU.0000000000004490
• Cleveland Clinic. (2024). Hematuria (blood in urine): Causes, diagnosis & treatment. https://my.clevelandclinic.org/health/diseases/15234-hematuria
• Mayo Clinic. (2023). Blood in urine (hematuria). https://www.mayoclinic.org/diseases-conditions/blood-in-urine/symptoms-causes/syc-20353432
• National Institute of Diabetes and Digestive and Kidney Diseases. (2022). Hematuria (blood in the urine). National Institutes of Health. https://www.niddk.nih.gov/health-information/urologic-diseases/hematuria-blood-urine