Hematuria (Blood in Urine)

Overview

Hematuria is the medical term for blood in the urine. The blood may be visible to the naked eye, causing urine to appear pink, red, or cola-colored (gross hematuria), or it may be detectable only under a microscope during routine testing (microscopic hematuria). Even a small amount of blood can noticeably change urine color.

While seeing blood in your urine can be alarming, it does not always indicate a serious problem. However, hematuria always warrants medical evaluation because it can signal conditions ranging from easily treated urinary tract infections to bladder cancer. The urinary system filters approximately 200 liters of blood daily, so blood can enter the urine from any point along the tract: the kidneys, ureters, bladder, or urethra.

Gross hematuria is defined as visible blood in the urine and always requires prompt evaluation. Microscopic hematuria is identified when a urinalysis shows three or more red blood cells per high-power field and is often discovered incidentally during routine health screening. Both types need investigation, though gross hematuria typically prompts more urgent workup given its association with malignancy in adults over 40.

Symptoms

The primary sign of hematuria is abnormal urine color. Gross hematuria causes urine to appear pink, red, brownish-red, or tea-colored depending on the amount of blood present. Some people notice blood clots in their urine, which may cause discomfort as they pass through the urethra.

Hematuria itself is often painless, particularly when caused by bladder cancer or kidney tumors. Painless gross hematuria in adults over 40 is considered a red flag that mandates thorough evaluation. When hematuria occurs with pain, the pattern provides diagnostic clues. Pain at the start of urination suggests urethral pathology, while pain at the end of urination (dysuria) often indicates bladder involvement. Flank or back pain accompanying blood in urine points toward kidney involvement, as seen with kidney stones or pyelonephritis.

Associated symptoms depend on the underlying cause. Urinary tract infections typically produce burning with urination, frequent urination, and urgency. Benign prostatic hyperplasia causes hesitancy, weak stream, and nocturia. Kidney disease may present with swelling, high blood pressure, and fatigue.

Causes

The causes of hematuria span from benign and self-limiting to serious conditions requiring urgent treatment.

Urinary Tract Infections. Bacterial infections of the bladder (bacterial cystitis) are among the most common causes of hematuria, particularly in women. The bacteria cause inflammation and irritation of the bladder lining, leading to bleeding. UTIs typically produce other symptoms including burning, urgency, and frequency.

Kidney and Bladder Stones. Kidney stones and bladder stones cause bleeding as they move through or irritate the urinary tract lining. Kidney stones often produce severe flank pain radiating to the groin, while bladder stones may cause lower abdominal discomfort and intermittent urinary stream.

Bladder Cancer. Bladder cancer is the most common cause of painless gross hematuria in adults. Risk increases substantially with age, with most cases occurring after age 55. Smoking is the leading modifiable risk factor, responsible for approximately half of all bladder cancers. Anyone over 40 with gross hematuria requires cystoscopy to rule out bladder malignancy.

Prostate Conditions. In men, benign prostatic hyperplasia commonly causes hematuria as enlarged prostate tissue becomes more vascular and prone to bleeding. Prostate cancer and acute prostatitis can also present with blood in the urine.

Kidney Disease. Glomerulonephritis, an inflammation of the kidney’s filtering units, causes blood and protein to leak into urine. This may occur as a primary kidney disorder or secondary to systemic conditions like lupus, IgA nephropathy, or post-streptococcal infection.

Medications. Blood thinners including warfarin, heparin, and aspirin can cause or unmask hematuria. Certain chemotherapy agents, particularly cyclophosphamide, can cause hemorrhagic cystitis with significant bleeding.

Other Causes. Exercise-induced hematuria occurs after strenuous activity and typically resolves within 48 hours. Pelvic radiation therapy can cause radiation cystitis with chronic bleeding. Trauma, recent urological procedures, inherited conditions like sickle cell disease, and menstrual contamination in women are additional causes to consider.

Diagnosis

Evaluation of hematuria involves confirming the presence of blood, identifying its source, and determining the underlying cause.

Initial Testing. A urinalysis confirms the presence of red blood cells and may reveal infection (white blood cells, bacteria), kidney disease (protein, casts), or suggest malignancy. Urine culture identifies bacterial pathogens when infection is suspected. Urine cytology examines cells shed into urine and can detect bladder cancer, though it has limited sensitivity for low-grade tumors.

Imaging Studies. CT urography is the gold standard imaging test, providing detailed views of the kidneys, ureters, and bladder in a single examination. It effectively identifies stones, tumors, and structural abnormalities throughout the urinary tract. Ultrasound offers a radiation-free alternative, particularly useful for initial evaluation or in patients who cannot receive CT contrast. MRI urography is reserved for patients with contrast allergies or kidney impairment.

Cystoscopy. Direct visualization of the bladder interior through a cystoscope is essential for evaluating gross hematuria in adults. This procedure identifies bladder tumors, stones, areas of inflammation, and sources of bleeding not visible on imaging. Cystoscopy is performed in the office under local anesthesia and takes approximately 5 to 10 minutes.

Additional Evaluation. Blood tests assess kidney function and, in men, prostate-specific antigen (PSA) levels. When glomerular disease is suspected based on proteinuria, red cell casts, or kidney function decline, nephrology consultation and possible kidney biopsy may be needed.

Treatment

Treatment for hematuria targets the underlying cause rather than the bleeding itself.

Infection. Urinary tract infections respond to appropriate antibiotics based on culture results. Adequate hydration helps flush bacteria from the bladder. Follow-up urinalysis confirms resolution of infection and hematuria.

Stones. Small kidney stones may pass spontaneously with increased fluid intake and pain management. Alpha-blocker medications can help relax the ureter and facilitate passage. Larger stones or those causing obstruction require intervention through shock wave lithotripsy, ureteroscopy with laser fragmentation, or percutaneous nephrolithotomy. Bladder stones typically require cystoscopic removal.

Cancer. Bladder cancer treatment depends on stage and grade. Non-muscle-invasive tumors are resected through the cystoscope, often followed by intravesical therapy. Muscle-invasive disease requires radical cystectomy or combined chemotherapy and radiation. Kidney cancers are typically treated surgically, with partial or radical nephrectomy depending on tumor size and location.

Prostate Conditions. BPH is managed with alpha-blocker or 5-alpha reductase inhibitor medications. Procedures including transurethral resection, laser ablation, or prostatic urethral lift address more significant obstruction or bleeding.

Kidney Disease. Glomerulonephritis treatment varies by type and may include blood pressure control, dietary modifications, and immunosuppressive medications. Close nephrology follow-up monitors kidney function and disease progression.

Medication-Related Bleeding. When anticoagulants cause significant hematuria, the clinical team weighs bleeding severity against thrombotic risk to determine whether dose adjustment or temporary discontinuation is appropriate.

When to See a Doctor

Any episode of visible blood in the urine warrants prompt medical evaluation. While the cause may prove benign, gross hematuria in adults over 40 requires complete urological workup including cystoscopy to exclude malignancy. Painless hematuria is particularly concerning, as bladder and kidney cancers often present without associated discomfort.

Seek same-day evaluation if you experience blood in your urine along with fever, which may indicate pyelonephritis (kidney infection). Severe flank pain with hematuria suggests a kidney stone that may require intervention. Difficulty urinating or complete inability to void accompanied by blood warrants emergency evaluation for possible clot retention.

Go to the emergency department if you notice large blood clots blocking urine flow, experience signs of significant blood loss such as dizziness or weakness, have severe uncontrolled pain, or develop high fever with blood in your urine. Recent trauma to the abdomen or pelvis with subsequent hematuria also requires emergency assessment.

Microscopic hematuria discovered on routine testing should be discussed with your physician. While less urgent than gross hematuria, it still requires evaluation particularly in patients with risk factors for urinary tract malignancy including age over 40, smoking history, occupational chemical exposure, or prior pelvic radiation or cyclophosphamide treatment. Repeat urinalysis, imaging, and sometimes cystoscopy ensure no serious pathology is missed.