Blood in urine — a finding doctors call hematuria — is one of the more anxiety-inducing results a patient can receive from a routine urine test. The finding spans a wide spectrum: it may mean something as common and easily treated as a urinary tract infection, or it may be the first sign of a kidney stone, a glomerular kidney disease, or — in a smaller number of cases — a urinary tract cancer. Understanding what your test results actually show, and what happens next, takes much of the uncertainty out of the process.
Two Types: Gross and Microscopic Hematuria
Blood in urine is classified into two types based on whether it is visible to the eye.
Gross hematuria means the blood is visible — the urine appears pink, red, bright red, or dark brown (sometimes described as cola- or tea-colored). Even a small amount of blood — as little as one milliliter per liter of urine — can visibly discolor the urine. Gross hematuria is always considered clinically significant and always warrants a full evaluation, even if it resolves on its own before the appointment.
Microscopic hematuria (MH) means the blood is not visible but is detected under the microscope or by a chemical dipstick test. The standard threshold for microscopic hematuria is three or more red blood cells per high-power field (RBCs/HPF) on a properly collected urine sample examined by microscopy. At this level, no visible change in urine color occurs. Most hematuria encountered in routine health screening is microscopic.
An important distinction exists between the dipstick test for blood and actual microscopic hematuria. The urine dipstick detects hemoglobin (from red blood cells) chemically — but it also reacts to myoglobin (from muscle breakdown) and free hemoglobin from hemolyzed red blood cells. A dipstick that is positive for blood without red blood cells visible on microscopy is not true hematuria and requires a different workup. Always confirm a positive dipstick with a microscopic exam of the urine sediment.
In women, menstrual blood contamination is a common source of false-positive results. If a woman had her period within the prior few days, the test should be repeated after menstruation ends before hematuria is concluded.
What the Numbers Mean on Your Urine Test
The microscopy report quantifies red blood cells in terms of RBCs per high-power field:
- 0–2 RBCs/HPF: Normal; not significant
- 3–10 RBCs/HPF: Microscopic hematuria — low to moderate level; triggers initial risk assessment
- 11–25 RBCs/HPF: Moderate microscopic hematuria; higher suspicion for structural or urologic cause
- >25 RBCs/HPF: High-level microscopic hematuria; classified as high risk under AUA guidelines; warrants prompt comprehensive evaluation
Beyond RBC count, the character of the red blood cells provides important information. Dysmorphic RBCs — particularly acanthocytes — are red blood cells distorted by being forced through the glomerular filtration barrier. Their presence strongly suggests the blood is coming from the kidney’s filtering unit rather than from a stone, tumor, or infection.
RBC casts — cylinders of red blood cells held together by a protein matrix in the kidney’s tubules — are pathognomonic for glomerulonephritis, meaning their presence essentially confirms that the kidney itself is inflamed and actively leaking red blood cells into the urine. Even one RBC cast changes the direction of the workup entirely, shifting it from urologic evaluation (cystoscopy, CT scan) to nephrologic evaluation (kidney function tests, antibody testing, possible biopsy).
The presence of significant proteinuria alongside hematuria — an ACR above 30 mg/g combined with RBC casts or dysmorphic RBCs — further points toward glomerular disease rather than a stone or cancer.
Common Causes of Blood in Urine
Urinary tract infection (UTI) is the most common cause of hematuria in women. The inflamed, infected bladder wall bleeds easily, causing blood to enter the urine. UTI-related hematuria resolves once the infection is treated. A UTI should be ruled out with a urine culture before a full hematuria workup is initiated.
Kidney stones (nephrolithiasis) are the most common benign cause of gross hematuria in adults. A stone passing through the ureter abrades the urothelial lining, releasing blood into the urine. The blood is often accompanied by colicky flank pain radiating to the groin. Smaller stones may pass silently and still produce microscopic hematuria.
Bladder cancer and urothelial tumors are the most important causes to exclude in patients with risk factors. Bladder cancer typically causes painless gross hematuria — blood appears in the urine without other symptoms. It has strong associations with cigarette smoking, occupational chemical exposure, and increasing age.
Benign prostatic hyperplasia (BPH) in men over 50 causes hematuria when the enlarged prostate compresses the urethra and causes venous congestion in the bladder neck. It is a common and benign cause in older men, though other causes must be excluded before attributing hematuria to BPH alone.
IgA nephropathy is the most common form of glomerulonephritis worldwide and classically presents as episodic gross hematuria beginning 1–3 days after a respiratory or gastrointestinal infection — a pattern called synpharyngitic hematuria. The timing distinguishes it from post-infectious glomerulonephritis, which occurs 2–3 weeks after the infection.
Exercise-induced hematuria is a benign cause seen in runners and endurance athletes, from bladder wall trauma or myoglobinuria. It resolves within 48–72 hours of stopping exercise. If hematuria persists beyond 72 hours of rest, exercise is unlikely to be the sole cause.
Anticoagulant therapy — including warfarin, apixaban, and rivaroxaban — lowers the threshold at which existing structural lesions bleed visibly. Critically, anticoagulation does not explain hematuria; it lowers the threshold for hematuria from pre-existing lesions. Patients on anticoagulants with hematuria require the same evaluation as anticoagulant-naïve patients.
Glomerular Hematuria: When It Comes from the Kidney Itself
When blood originates from the kidney’s filtering units rather than the collecting system or bladder, the evaluation follows a different path. Glomerular hematuria is distinguished by RBC casts in the urine sediment, dysmorphic RBCs (acanthocytes), concurrent proteinuria, and absence of pain.
IgA nephropathy: Deposits of IgA antibodies in the mesangium cause glomerular inflammation. Approximately 20–40% of patients progress to CKD over decades. New therapies including SGLT-2 inhibitors, targeted-release budesonide (Nefecon), and sparsentan have changed the management landscape.
Thin basement membrane nephropathy (TBMN): Also called benign familial hematuria; caused by mutations in type IV collagen genes. Presents as persistent microscopic hematuria in young adults with a family history. The prognosis is generally benign, though a small subset progress to CKD.
Alport syndrome: A hereditary nephritis caused by COL4A3/COL4A4/COL4A5 mutations. Features microscopic or gross hematuria from childhood, progressive CKD, sensorineural hearing loss, and ocular abnormalities.
Lupus nephritis: Hematuria in a patient with systemic lupus erythematosus, often accompanied by proteinuria, RBC casts, and active urinary sediment. Triggers complement measurement (C3, C4), anti-dsDNA antibodies, and usually kidney biopsy to classify the histological pattern.
How Doctors Evaluate Blood in Urine
The American Urological Association (AUA) 2020 guidelines provide a risk-stratified framework for evaluating microscopic hematuria in adults aged 35 and older.
Step one: Exclude non-pathological causes. Urine culture should confirm the absence of UTI. In women, repeat the test after menstruation if contamination is possible. If vigorous exercise occurred within 72 hours or recent instrumentation (catheter, cystoscopy) was performed, repeat the test first.
Risk stratification:
- Low risk: Under 45, never smoker or fewer than 10 pack-years, 3–10 RBCs/HPF, no risk factors → Repeat UA in 6 months; no imaging or cystoscopy required if clear
- Intermediate risk: Single risk factor present, or MH on two or more occasions → Cystoscopy AND renal imaging (CT urogram or renal ultrasound)
- High risk: Gross hematuria, age ≥60, >25 RBCs/HPF, or ≥2 risk factors → CT urogram AND cystoscopy
For more on urinalysis interpretation, see our guide to urinalysis results. For information on kidney protein levels alongside hematuria, see protein in urine: causes and meaning.
Imaging and Other Tests
CT urogram is the gold-standard imaging study for evaluating hematuria. It combines pre-contrast, contrast, and delayed excretory-phase images to simultaneously visualize the kidneys, ureters, and bladder. It detects kidney masses, ureteral stones, and urothelial tumors with high sensitivity.
Renal ultrasound is the preferred first-line imaging in younger patients under 40, pregnant women, and those with contrast dye allergies or renal insufficiency. It accurately identifies kidney masses and large stones but does not visualize the ureter well and may miss small urothelial tumors.
Cystoscopy involves direct visual inspection of the bladder using a flexible scope inserted through the urethra. Performed under local anesthesia in an office setting, it is required for intermediate- and high-risk patients because it directly visualizes the bladder mucosa — the site where most urological cancers arise.
Blood tests are added when glomerular hematuria is suspected: serum creatinine and eGFR assess kidney function; ANA, ANCA, anti-GBM, C3, C4, anti-dsDNA, and hepatitis B/C serologies help identify the autoimmune or infectious cause. For more on kidney function testing, see our guide to kidney function tests.
When Blood in Urine Is an Emergency
Most cases of hematuria, including gross hematuria, are not medical emergencies. However, certain presentations require urgent or emergency evaluation:
Clot retention: When blood clots fill the bladder, they can obstruct the urethra completely, preventing urination. This causes severe suprapubic pain and inability to void. It requires urgent placement of a three-way Foley catheter for continuous bladder irrigation. Do not wait; go to an emergency department.
Gross hematuria with fever and flank pain: This combination suggests an obstructing kidney stone with a superimposed infection (urosepsis). Urgent urologic consultation for decompression (ureteral stent or nephrostomy tube) is needed alongside antibiotics.
Hematuria after trauma: Blood in the urine after a fall, collision, or sports injury suggests renal laceration or bladder rupture and requires emergency imaging.
Rapidly rising creatinine with hematuria: The combination of hematuria, RBC casts, proteinuria, and a creatinine doubling over days suggests rapidly progressive glomerulonephritis (RPGN) — a kidney emergency that can destroy kidney function within weeks without aggressive treatment.
Risk Factors That Raise Concern for Bladder Cancer
Because bladder cancer is the most important malignancy to exclude in patients with hematuria, recognizing its risk factors calibrates the urgency of evaluation:
- Older age: Risk increases substantially after 40; median diagnosis age around 73
- Male sex: Bladder cancer is three times more common in men than in women
- Cigarette smoking: The strongest modifiable risk factor; accounts for approximately 50% of bladder cancer cases; both current and past smokers carry elevated risk
- Occupational chemical exposure: Benzene derivatives and aromatic amines (rubber manufacturing, paint, dye, leather, aluminum industries) substantially increase risk
- Prior pelvic radiation: For prostate, cervical, or rectal cancer
- Cyclophosphamide: Chemotherapy metabolites are excreted in urine and directly toxic to bladder epithelium
- Chronic indwelling catheter: Associated with squamous cell carcinoma of the bladder
The AUA guidelines note that no single risk factor absence fully excludes the need for evaluation; it reduces — but does not eliminate — the chance of malignancy.
What Happens After a Negative Workup
Many patients who complete a full hematuria evaluation — cystoscopy, CT urogram, and laboratory studies — receive a result of “no cause found.” This is called idiopathic or essential hematuria, and it is a common outcome, particularly in younger patients and women.
Idiopathic microscopic hematuria in a low-risk patient carries a favorable long-term prognosis. The 5-year risk of subsequently being diagnosed with a urological malignancy is less than 2% in low-risk patients.
However, a negative workup does not mean no follow-up is needed. Current AUA guidelines recommend:
- Annual urinalysis for at least 5 years after the initial workup
- Blood pressure measurement and serum creatinine each year (to catch early CKD or glomerular disease)
- Repeat cystoscopy and imaging if gross hematuria develops, MH worsens, or new symptoms appear
Frequently Asked Questions About Blood in Urine
Is blood in urine always serious?
Not always. Common and easily treated causes — UTI, kidney stone, exercise-induced bleeding — account for the majority of cases. However, because a small but real percentage of cases represent urinary tract cancer or serious kidney disease, every confirmed case deserves at least an initial evaluation.
Can blood in urine go away on its own?
Yes — and this is part of what makes hematuria dangerous to dismiss. Bladder cancer frequently produces intermittent visible hematuria that appears and disappears over weeks or months. The fact that the blood stopped does not mean the cause went away. Resolution before a clinic appointment does not cancel the need for evaluation.
What medications cause blood in urine?
Beyond anticoagulants, rifampicin (an antibiotic) can turn urine red from the drug itself — not blood. Phenazopyridine (AZO) turns urine orange-red. NSAIDs and certain other drugs can cause drug-induced kidney disease with hematuria. Always inform your doctor of all medications and supplements.
How accurate is a dipstick test for blood?
The dipstick is highly sensitive — it rarely misses true hematuria — but not very specific. It can be positive from myoglobin, free hemoglobin, bacterial peroxidases, concentrated urine, and oxidizing cleaning agents. A positive dipstick must always be confirmed with microscopy before the finding is considered true hematuria.
What does it mean if I have blood in urine but no pain?
Painless hematuria — particularly painless gross hematuria — is a classic presentation of bladder cancer. The absence of pain does not indicate the cause is benign. Painless gross hematuria in a person over 50 who smokes should be treated as a suspected malignancy until proven otherwise.
This article is for educational purposes only. Always consult a qualified healthcare provider for diagnosis and treatment of any medical condition.
Special Populations: Hematuria in Different Clinical Contexts
The evaluation and significance of blood in urine varies substantially depending on the patient’s age, sex, and medical history. Understanding these differences helps put your own result in context.
Children with hematuria have a different differential than adults. In children aged 1 to 10, post-infectious glomerulonephritis (often following streptococcal infection) is the most common cause of nephritic syndrome, presenting as hematuria with RBC casts, facial edema, and hypertension appearing 1–3 weeks after a strep throat or skin infection. IgA nephropathy is the most common cause of persistent microscopic hematuria in school-age children and adolescents, and thin basement membrane nephropathy is frequently discovered incidentally during evaluation for a child’s sibling or parent with known hematuria. Wilms tumor (nephroblastoma), while rare, is the most common kidney tumor in children under 5 and may present with gross hematuria alongside an abdominal mass. Children in whom urinalysis shows persistent microscopic hematuria accompanied by proteinuria or an elevated creatinine should be referred to pediatric nephrology for evaluation.
Women of reproductive age face the additional complication that menstrual blood contamination of a midstream catch specimen is extremely common and can mimic true hematuria. The dipstick will show hemoglobin, and sometimes even a few RBCs will appear on microscopy from contamination. In a woman who reports hematuria consistently during or around her menstrual period, collection of a catheterized specimen — or repeat testing at mid-cycle — helps establish whether the finding is real. Endometriosis involving the bladder or ureters is a rare but important cause of cyclical hematuria in women, occurring with or just before menstruation and sometimes associated with dysuria or suprapubic pain.
Pregnant women commonly have mild microscopic hematuria from the physiological increase in renal blood flow, which raises GFR and slightly increases RBC excretion. However, hematuria in pregnancy also raises the possibility of UTI, which is particularly important to treat in pregnancy due to the risk of pyelonephritis. Kidney stones complicate approximately 1 in 1,500 pregnancies and present with flank pain and hematuria. Gross hematuria in pregnancy is never attributed to normal physiology and always warrants evaluation — typically with renal ultrasound as first-line imaging to avoid radiation exposure to the fetus.
Older adults over 65 who present with even a single episode of visible gross hematuria face a substantially higher pretest probability of urological malignancy than younger patients. Bladder cancer incidence rises steeply after age 60, and the classic presentation — painless, intermittent gross hematuria in a long-term smoker — is most common in this group. Age alone (60 and older) is classified as a high-risk feature under AUA guidelines, meaning any older adult with hematuria should receive both CT urogram and cystoscopy regardless of other risk factors. The evaluation should not be deferred or minimized because of age or comorbidities; early-stage bladder cancer detected at cystoscopy is often cured by transurethral resection alone.
Patients with sickle cell trait or disease are at increased risk of papillary necrosis — infarction of the renal papillae from the sickling of red blood cells in the vasa recta, small vessels with low oxygen tension in the medulla. Papillary necrosis causes hematuria that can be gross and dramatic, as sloughed papillary tissue passes through the collecting system. It can affect patients with sickle cell trait (not just full sickle cell disease), and hematuria in a patient known to carry sickle cell trait is often attributed to papillary necrosis after urological causes are excluded.
Navigating Your Care After a Hematuria Finding
Knowing what to expect at each step of the evaluation reduces anxiety and helps patients advocate for appropriate care.
After an abnormal dipstick or urinalysis: Your doctor should order a repeat urinalysis with microscopy if you had vigorous exercise, a recent UTI, or possible menstrual contamination at the time of the original test. If the repeat is still positive, a urine culture rules out active infection. Once UTI is excluded and the hematuria is confirmed on microscopy, risk stratification determines the next step. If you are low risk and under 45 with only 3–10 RBCs/HPF, a repeat UA in 6 months may be all that is needed initially. Do not skip this follow-up appointment even if you feel well — it is the safety net that catches any progression.
Before cystoscopy: If cystoscopy is recommended, you will likely have the procedure in a urology office or outpatient facility. A flexible cystoscope (about the diameter of a pencil) is passed through the urethra into the bladder after local anesthetic gel is applied. The procedure typically takes 5–10 minutes and causes mild discomfort rather than significant pain. Afterward, many patients notice mild burning with urination and light pink-tinged urine for 24–48 hours — this is normal. You should call the office if you develop fever, chills, inability to urinate, or heavy bleeding after the procedure.
Before CT urogram: The CT urogram requires intravenous contrast dye. Inform your doctor if you have a history of contrast allergy, kidney disease (eGFR below 30 puts you at risk of contrast-induced nephropathy), or are taking metformin (which requires a 48-hour hold around contrast administration). The scan takes approximately 30–45 minutes and involves multiple passes through the scanner at different phases of contrast excretion to visualize the entire urinary tract.
If kidney disease is suspected: When glomerular hematuria is suspected — because of dysmorphic RBCs, RBC casts, or significant proteinuria alongside the hematuria — your primary care doctor should refer you to nephrology. The nephrologist will order additional blood and urine tests to identify the specific cause and determine whether kidney biopsy is needed. A kidney biopsy — in which a small needle sample of kidney tissue is obtained under ultrasound guidance — is the definitive step that distinguishes between IgA nephropathy, lupus nephritis, thin basement membrane disease, and other glomerular conditions. It informs both the treatment plan and the prognosis. The biopsy is an outpatient procedure and typically requires 4–6 hours of observation afterward; serious complications (significant bleeding requiring transfusion) occur in fewer than 1% of cases at experienced centers.
Sources: AUA Microhematuria Guidelines 2020/2023; NIDDK — Blood in Urine; American Cancer Society — Bladder Cancer Symptoms; Mayo Clinic — Blood in Urine.
As someone dealing with this personally, the blood in urine test results section was very helpful. The section on managing this condition day-to-day was especially useful for planning. This gave me real confidence going into my next specialist appointment.
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As someone dealing with this personally, the blood in urine test results section was very helpful. What I liked most was that the article didn’t just say what to avoid — it also gave alternatives. This is going into my health folder that I bring to every doctor’s visit.