Hematuria is the medical term for blood in your urine. It’s one of the most common reasons people see a urologist, accounting for more than 20% of all urological evaluations. Sometimes the blood is visible, turning your urine pink, red, or brown. Other times it’s only detectable under a microscope during a routine urine test.
Visible vs. Microscopic Hematuria
The most important distinction is whether you can actually see the blood. Gross hematuria means the blood is visible to the naked eye. Your urine might look obviously red or pink, or it can appear brown or tea-colored when the blood pigments have oxidized. Even a small amount of blood can change the color noticeably.
Microscopic hematuria, on the other hand, looks completely normal to you. The urine is its usual yellow color, but a lab test picks up red blood cells that shouldn’t be there. The formal threshold is more than 3 red blood cells per high-power field on a single, properly collected urine sample, according to American Urological Association guidelines. This type is often discovered incidentally during a routine physical or when testing for something else entirely.
Common Causes
Most cases of hematuria trace back to something treatable and non-life-threatening. Urinary tract infections are among the most frequent culprits. Bacteria enter through the urethra, multiply in the bladder, and cause inflammation that leads to bleeding. You’ll usually also have burning with urination, urgency, or pelvic discomfort.
Kidney stones can scrape the lining of the urinary tract as they move, producing blood in the urine along with intense flank or abdominal pain. An enlarged prostate is another common source in men, sometimes accompanied by difficulty urinating or a persistent feeling of needing to go. Prostate infections (prostatitis) cause similar symptoms.
Strenuous exercise can also trigger hematuria, particularly in runners and other endurance athletes. Exercise-induced hematuria typically resolves on its own within a week. Kidney disease, particularly conditions that affect the filtering units of the kidneys, is another possible cause. In these cases, protein in the urine often accompanies the blood.
When Blood in Urine Signals Something Serious
The concern most people have when they notice blood in their urine is cancer, and while it’s not the most common explanation, it is a real possibility that warrants evaluation. A large population-based study found that among people with visible (gross) hematuria, about 9% were diagnosed with bladder cancer and roughly 1.3% with kidney cancer. For microscopic hematuria, those numbers drop significantly: bladder cancer was found in about 1.6% of cases, and kidney cancer in 0.2%.
Painless gross hematuria is the presentation that raises the most concern. When blood appears in your urine without any burning, cramping, or other discomfort, it removes infections and stones from the likely explanation and makes a growth in the bladder or kidneys more probable. That doesn’t mean painless hematuria is always cancer, but it does mean it needs a thorough workup.
Risk Factors That Affect Your Evaluation
Not everyone with hematuria faces the same level of risk. Doctors now use a tiered system to decide how aggressively to investigate, based on several personal factors:
- Age: Risk increases significantly after 50 for women and after 40 for men. People over 60 of either sex are considered highest risk.
- Smoking history: Tobacco exposure is one of the strongest risk factors for bladder cancer. More than 30 pack-years (a pack a day for 30 years, or equivalent) puts you in the high-risk category. Even 10 to 30 pack-years elevates your risk to intermediate.
- Amount of blood: Higher red blood cell counts on urinalysis correlate with higher risk. More than 25 red blood cells per high-power field is considered high risk.
- Occupational exposures: Working with benzene chemicals or aromatic amines (common in dye manufacturing, rubber, and certain chemical industries) increases bladder cancer risk.
- Medical history: Prior pelvic radiation, certain chemotherapy drugs, a family history of bladder cancer or Lynch syndrome, and chronic use of urinary catheters all raise risk.
A younger person with a small amount of microscopic blood and no risk factors will typically get a less intensive evaluation than an older smoker with visible blood. This stratified approach helps avoid unnecessary invasive tests for low-risk patients while ensuring high-risk patients get a thorough workup promptly.
How Hematuria Is Diagnosed
The starting point is a urinalysis, a simple urine test that confirms whether blood is present and checks for signs of infection or minerals associated with kidney stones. If blood was only found once, your doctor may repeat the test to see if it persists.
Imaging is often the next step. A CT scan, MRI, or ultrasound can reveal kidney stones, tumors, or structural problems in the kidneys and urinary tract. CT is the most commonly used option because it provides detailed views of the entire urinary system in a single scan.
For patients at intermediate or high risk, cystoscopy is a key part of the evaluation. During this procedure, a thin, flexible tube with a small camera on the end is threaded through the urethra into the bladder. It gives a direct view of the bladder lining, making it the most reliable way to detect bladder tumors or other abnormalities. The procedure is done in an office setting and takes only a few minutes, though it can feel uncomfortable.
How Hematuria Is Treated
Hematuria itself isn’t a disease. It’s a symptom, and treatment depends entirely on what’s causing it. A urinary tract infection is treated with antibiotics, and the blood clears as the infection resolves. Kidney stones may pass on their own with fluids and pain management, or they may need a procedure to break them up or remove them if they’re too large. An enlarged prostate can be managed with medications that shrink the gland or relax the muscles around it.
If a tumor is found, the treatment path depends on the type, size, and location of the growth. For small, early-stage bladder tumors, removal during cystoscopy is often the first step. More advanced cancers require additional treatment.
In some cases, particularly with microscopic hematuria in younger, low-risk patients, no specific cause is found. When imaging and other tests come back normal, periodic monitoring with repeat urinalysis is the standard approach to ensure the blood resolves and nothing new develops.
Signs That Need Prompt Evaluation
Any visible blood in your urine warrants a medical visit, even if it only happens once and goes away. Certain accompanying signs raise the urgency further: blood in the urine combined with protein in the urine, persistent microscopic hematuria (especially after age 50), new swelling in the legs or face along with high blood pressure, and systemic symptoms like unexplained weight loss, night sweats, or fever. These combinations can point to kidney disease or malignancy that benefits from early detection.