Lab result explainedUrinalysisLast updated November 10, 2026

Blood in urine (hematuria): what RBCs and occult blood on a urine test mean

Blood in urine (hematuria) (RBC, urine) · Urinalysis (dipstick and microscopy) · reported in RBC per high-power field (RBC/HPF) on microscopy; negative, trace, 1+, 2+ or 3+ (small, moderate, large) on dipstick

Blood in urine (hematuria) means red blood cells are present in your urine, either in amounts you can see (gross or visible hematuria, where the urine looks pink, red, tea-colored or cola-colored) or in amounts only a laboratory can detect (microscopic hematuria). On a urinalysis it shows up in two ways. The dipstick pad labelled 'blood' or 'occult blood' reacts chemically to hemoglobin, and the microscopy section counts red cells per high-power field (RBC/HPF). Normal is 0 to 2 RBC/HPF with a negative dipstick. The American Urological Association defines microscopic hematuria as 3 or more RBC/HPF on a properly collected, uncontaminated sample.

Most blood in urine has a benign explanation: a urinary tract infection, a kidney stone, menstrual contamination of the sample, vigorous exercise in the previous day or two, an enlarged prostate, or a minor injury to the lining of the bladder. The reason clinicians take it seriously is that a minority of cases, roughly 2 to 5 percent of people with persistent microscopic hematuria and 10 to 20 percent of those with visible blood, turn out to have a cancer of the bladder, kidney or urinary tract, and these are far more treatable when found early. Blood in urine with no infection, no pain and no obvious cause is therefore not something to watch and wait on; it is the result most likely to need a urology work-up.

A positive dipstick with no red cells on microscopy has a different meaning: the pad is reacting to free hemoglobin (from red cells breaking down in the bloodstream) or myoglobin (from muscle breakdown) rather than to blood in the urinary tract. And red urine is not always blood; beets, blackberries, food dyes and several medicines color urine red or orange with a negative test. A single positive result is usually repeated once any temporary cause (infection, period, exercise) has passed; if it persists, the next steps depend on your age, smoking history and how many cells were seen.

RBC, urine at a glance

What it is: red blood cells (or the hemoglobin they contain) detected in a urine sample by dipstick, by microscopy, or both.
Normal: 0–2 RBC per high-power field (some labs accept up to 4) and a negative dipstick. 3 or more RBC/HPF is microscopic hematuria; visible pink or red urine is gross hematuria.
Dipstick grades: trace (about 5–10 RBC/µL), 1+ or small (about 25), 2+ or moderate (about 80), 3+ or large (about 200). Microscopy confirms whether real red cells are present.
Common causes: urinary tract infection, kidney stones, enlarged prostate, menstruation contaminating the sample, hard exercise, and kidney (glomerular) disease. Less common but important: bladder, kidney and prostate cancer.
A positive dipstick with no red cells on microscopy points to hemoglobin or myoglobin in the urine, not bleeding; red urine with a negative test is usually food or a drug.
Next step: repeat the urinalysis once infection, a period or exercise is excluded; if blood persists, expect a creatinine, urine protein check, and for most adults a cystoscopy plus kidney imaging.

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What RBC, urine measures

The dipstick 'blood' pad contains a chemical (tetramethylbenzidine with a peroxide) that changes color when it meets the iron-containing heme group of hemoglobin. Intact red cells lyse on the pad and release hemoglobin, producing a speckled pattern; free hemoglobin or myoglobin already dissolved in the urine produces a uniform color change. The pad is sensitive, detecting roughly 5 red cells per microlitre (about 1 to 2 cells per high-power field), which is why a trace result is common and does not by itself mean disease.

Microscopy is the confirmatory part. A 10 to 15 mL aliquot of urine is spun down, the sediment is examined at 400x magnification, and red cells are counted and averaged over 10 to 20 fields. Three or more per field defines microscopic hematuria. The lab also notes the shape of the cells: uniform, disc-shaped cells suggest bleeding from the bladder, prostate or urethra, while distorted (dysmorphic) cells, particularly ring forms with blebs called acanthocytes, and red-cell casts indicate the blood passed through the kidney's filters and point to glomerular disease.

The dipstick gives false positives with menstrual blood, dehydrated concentrated urine, povidone-iodine skin cleansers, bleach or other oxidising residues in the container, and bacterial peroxidases in an infected sample left standing. It gives false negatives in people taking large doses of vitamin C (ascorbic acid interferes with the reaction), with very dilute or very acidic urine, and with captopril. A clean-catch midstream sample, collected away from menstruation and not within 48 hours of strenuous exercise or sexual activity, avoids most of these problems. Refrigerate or test within two hours, because red cells lyse in urine that sits at room temperature.

Normal range for RBC, urine

Reference ranges vary between labs and by age, sex and pregnancy. Use the range printed on your own report.

Group	Typical range (RBC per high-power field (RBC/HPF) on microscopy; negative, trace, 1+, 2+ or 3+ (small, moderate, large) on dipstick)	Notes
Microscopy, normal	0–2 RBC/HPF (some labs report 0–4 or 'fewer than 3')	Healthy adults pass up to about a million red cells into the urine a day, which is a cell or two per field. Labs differ; use the reference printed on your report.
Microscopic hematuria, lower band	3–10 RBC/HPF	Meets the AUA definition. In a younger adult who has never smoked and has no other risk factors, this is the 'low-risk' tier of the AUA/SUFU guideline (2020, amended 2025; the age and sex cut-offs changed in the amendment, so your urologist applies the current version): repeat in 6 months or proceed to cystoscopy and kidney ultrasound after discussion.
Microscopic hematuria, middle band	11–25 RBC/HPF	'Intermediate-risk' tier in the AUA/SUFU guideline (also triggered by middle age or a 10–30 pack-year smoking history; the exact age cut-offs were revised in the 2025 amendment): cystoscopy plus renal ultrasound.
Microscopic hematuria, upper band	More than 25 RBC/HPF	'High-risk' tier on its own (as is a heavy smoking history of more than 30 pack-years, any episode of visible blood, or older age combined with other risk factors under the 2025 amendment): cystoscopy plus CT urography.
Dipstick negative or trace	Trace ≈ 5–10 RBC/µL	Trace is at the limit of detection and is frequently seen after exercise, in concentrated urine or with menstrual contamination. It is repeated, and microscopy decides whether cells are actually present.
Dipstick 1+ (small)	≈ 25 RBC/µL	Usually corresponds to 3–10 cells per field. Needs microscopy and, if confirmed, the same evaluation as any microscopic hematuria.
Dipstick 2+ to 3+ (moderate to large)	≈ 80 to 200 RBC/µL or more	Often visible as a faint pink tinge. Infection, stones and heavy menstrual contamination are common explanations; a 3+ with no cells on microscopy means hemoglobin or myoglobin.
Gross (visible) hematuria	Urine visibly pink, red, brown or with clots	As little as 1 mL of blood in a liter of urine is visible. Even one episode that resolves on its own is treated as high risk and evaluated, because bleeding from bladder tumors is typically painless and intermittent.

Blood in urine (positive occult blood or raised RBC count)

A confirmed finding of 3 or more red cells per high-power field, or any visible blood, means something is allowing red cells into the urinary tract between the kidney's filters and the tip of the urethra. The commonest explanations are infection (usually with leukocytes, nitrite and symptoms), a stone (usually with pain radiating from the flank to the groin), an enlarged or inflamed prostate, and in women contamination from menstrual or vaginal bleeding. Recent strenuous exercise, especially running or contact sport, causes transient hematuria in a significant minority of athletes and clears within 24 to 72 hours.

When those explanations are excluded or the blood persists after they are treated, the two groups of causes that matter are urological (bladder, kidney, ureter or prostate tumors, stones and structural problems) and glomerular (diseases of the kidney's filtering units such as IgA nephropathy, thin basement membrane disease, Alport syndrome or lupus nephritis). The lab helps separate them: glomerular bleeding produces dysmorphic red cells, red-cell casts, protein in the urine (often more than 500 mg a day, or a protein-to-creatinine ratio above 0.5) and sometimes a raised creatinine; urological bleeding produces normal-shaped cells with little protein. Cola-colored urine a day or two after a sore throat in a younger person is a classic glomerular picture.

Cancer risk rises with age (especially over 60), male sex, smoking history, visible rather than microscopic blood, higher cell counts, occupational exposure to dyes, rubber or leather chemicals, past pelvic radiation or cyclophosphamide treatment, and irritative bladder symptoms with no infection. The 2020 AUA/SUFU guideline uses these factors to decide between repeating the test in six months, cystoscopy with a kidney ultrasound, or cystoscopy with a CT urogram. Taking a blood thinner does not explain hematuria on its own; anticoagulated patients with blood in the urine have the same evaluation, because the drug often unmasks a lesion that was already there.

Common causes

Urinary tract infection (cystitis, pyelonephritis, prostatitis)
Inflamed bladder or kidney lining bleeds easily. Blood is accompanied by leukocyte esterase, nitrite, white cells and often burning, urgency or fever. Repeat the urinalysis about 6 weeks after treatment to confirm the blood has gone; persistent blood after a cleared infection needs the full evaluation.
Kidney or ureteric stones
A stone scraping the urinary tract lining produces microscopic or visible blood in roughly 85 to 90 percent of cases, typically with severe colicky flank pain, nausea and crystals on microscopy. A CT scan without contrast is the usual next test.
Enlarged prostate (BPH) and prostatitis
The engorged blood vessels of an enlarged prostate bleed readily, especially after straining or catheterization. It is a common cause in men over 50 but is a diagnosis of exclusion; bladder cancer must still be ruled out in this age group.
Menstrual or vaginal contamination
Blood from a period, spotting, or vaginal bleeding mixes with the sample. A clean-catch sample collected several days after bleeding has stopped, or a catheter sample, settles the question.
Strenuous exercise and minor trauma
Long-distance running, contact sport, cycling and heavy lifting can cause transient hematuria from bladder wall bruising, red cell breakdown and increased glomerular leak. It resolves within 72 hours of rest; blood that persists beyond that is not exercise-related.
Glomerular kidney disease
IgA nephropathy (the most common glomerulonephritis worldwide), thin basement membrane disease (benign familial hematuria, affecting around 1 percent of people), Alport syndrome, post-infectious glomerulonephritis and lupus nephritis all leak red cells through damaged filters. Clues are dysmorphic cells, red-cell casts, proteinuria, high blood pressure or a rising creatinine.
Bladder, kidney, ureteric and prostate cancer
Bladder cancer presents with painless visible hematuria in about 80 to 90 percent of cases, and a quarter of people with visible blood over 60 have a tumor. Kidney cancer and upper-tract urothelial tumors also bleed intermittently. Smoking is the dominant risk factor; current smokers have roughly 3 to 4 times the bladder cancer risk of never-smokers.
Anticoagulants and antiplatelet drugs
Warfarin, DOACs (apixaban, rivaroxaban), clopidogrel and aspirin increase bleeding from any lesion. In studies of anticoagulated patients with hematuria, a significant urological cause (including cancer) was found at the same rate as in people not on the drug, so the work-up is not skipped.
Cystic and inherited kidney disease, sickle cell trait
Polycystic kidney disease causes bleeding when cysts rupture. Sickle cell trait (not just disease) causes painless hematuria from sickling in the low-oxygen inner kidney (papillary necrosis), and is a common finding in people of African ancestry with unexplained blood.
Bladder irritation from drugs, radiation and interstitial cystitis
Cyclophosphamide and ifosfamide cause hemorrhagic cystitis; pelvic radiotherapy can cause bleeding years later; interstitial cystitis (bladder pain syndrome) and schistosomiasis in travellers from endemic areas also produce blood. Hemoglobin in the urine without cells points to hemolysis, and myoglobin to rhabdomyolysis.

Symptoms that can go with it

Often none at all: microscopic hematuria is usually found on a routine urinalysis, and painless visible blood is the typical presentation of bladder cancer
Pink, red, brown or cola-colored urine, sometimes with clots (clots point to the bladder or prostate rather than the kidney)
Burning on urination, urgency, frequency, cloudy or foul-smelling urine, with fever or back pain in a kidney infection
Severe, waxing-and-waning pain from the flank into the groin, with nausea, in a stone episode
Weak stream, dribbling, straining or getting up at night in men with an enlarged prostate
Swelling of the ankles or face, foamy urine, new high blood pressure or reduced urine output, which point to glomerular kidney disease
Weight loss, fatigue, bone pain or a mass in the flank, which are late signs of kidney or bladder cancer

Read it alongside

Leukocyte esterase and nitrite (urine) — positive with blood points to infection; blood with both negative is the pattern that needs urological evaluation.
Urine culture — confirms or excludes infection; hematuria is re-tested about 6 weeks after a treated infection.
Urine microscopy for red-cell shape and casts — dysmorphic cells, acanthocytes or red-cell casts suggest glomerular bleeding and warrant nephrology referral. Risk-based urological evaluation is still needed, because the two can coexist.
Protein in urine and urine albumin-to-creatinine ratio — significant protein alongside blood suggests kidney filter disease; blood alone suggests a urological source.
Creatinine and eGFR — a raised creatinine with hematuria is a kidney disease signal and changes the urgency of referral.
Hemoglobin and CBC — rarely falls from urinary bleeding alone; anemia with hematuria suggests heavy or prolonged loss, kidney disease or a marrow problem.
PSA — checked in men with hematuria and urinary symptoms, since prostate enlargement and cancer both bleed.
PT/INR or anti-Xa level — in people on warfarin or a DOAC, an over-anticoagulated state makes bleeding more likely but does not remove the need to look for a cause.

What usually happens next

If there is an obvious temporary cause (infection, menstruation, hard exercise within 48 hours), the urinalysis is repeated after it has resolved, usually in 2 to 6 weeks, with a clean-catch midstream sample.
Blood confirmed on microscopy (3 or more RBC/HPF) with no explanation prompts a creatinine, blood pressure check and urine protein measurement. Findings that suggest glomerular disease warrant nephrology referral, but risk-based urological evaluation is still needed.
For most adults with persistent microscopic hematuria the urological evaluation is cystoscopy (a camera inspection of the bladder, done in clinic in a few minutes) plus kidney imaging: ultrasound for low and intermediate risk, CT urography for high risk. Urine cytology is not a screening substitute for cystoscopy.
A low-risk person (woman under 50 or man under 40, never or light smoker, 3 to 10 RBC/HPF, no other risk factors) may be offered a repeat urinalysis in 6 months instead of immediate cystoscopy; if blood is still present, evaluation proceeds.
If the evaluation is normal, a repeat urinalysis in 12 months is usual; blood that persists for two years with normal tests can be left with yearly checks, but any new visible blood or new symptoms restart the process.
Useful questions to ask: were red cells confirmed on microscopy, was the cell shape normal, was there protein, and which risk tier do my age, smoking history and cell count put me in.

Diet, lifestyle and natural levers with evidence

What can move RBC, urine once the cause is known. Nothing here replaces finding the cause.

Fluid intake to keep urine pale (if stones are the cause)

Strong evidence

In a 5-year randomised trial of first-time calcium stone formers, drinking enough to produce at least 2 liters of urine a day cut recurrence from 27 percent to 12 percent, and later trials confirm that a urine output of 2 to 2.5 liters roughly halves new stone formation. Fewer stones means fewer bleeding episodes. Spread water through the day and drink enough that urine stays pale yellow.

Stopping smoking

Strong evidence

Smoking is the single largest modifiable cause of bladder cancer, the most important serious cause of blood in urine. In a cohort of nearly half a million US adults, current smokers had about 4 times the risk of never-smokers and former smokers about 2 times, with roughly half of all bladder cancers attributable to smoking. Risk falls steadily in the years after quitting but takes 20 years or more to approach that of a never-smoker, which is why smoking history determines how thoroughly hematuria is investigated.

Cranberry products for recurrent urinary infection

Moderate evidence

A 2023 Cochrane review of 50 trials found cranberry juice, tablets or capsules reduced the number of symptomatic urinary tract infections by about a quarter in women with recurrent infections and in children, with no clear benefit in older adults in care homes or people with bladder catheters. If infection is what keeps producing blood on your urine tests, this is one of the few supplements with reasonable evidence.

Cranberry can raise the INR in people taking warfarin, and juice adds sugar and oxalate; it does not treat an existing infection.

Timing the sample to avoid false positives

Moderate evidence

Exercise-induced hematuria is reported in 5 to 20 percent of runners after a race and in up to 80 percent after very long events, clearing within 72 hours. Menstrual contamination, sexual intercourse within 24 hours and high-dose vitamin C (which can produce a false negative) all distort the dipstick. Collecting a clean-catch midstream sample after 2 to 3 days without hard exercise and away from menstruation, and telling the lab about vitamin C, anticoagulants and recent catheter use, prevents many unnecessary repeat tests. Nothing dietary or herbal removes true hematuria; the cause has to be found.

When to see a clinician promptly

Visible blood in the urine, even once and even if it clears on its own: this is treated as high risk at any age and needs evaluation within days, not months.
Blood in the urine with inability to pass urine, large clots, or heavy bleeding: go to an emergency department (clot retention can block the bladder).
Blood with fever, shaking chills, flank pain or vomiting: possible kidney infection or an infected obstructing stone, which needs same-day treatment.
Blood with swelling of the legs or face, foamy urine, new high blood pressure or reduced urine output: possible glomerulonephritis, which can damage the kidneys quickly.
Microscopic blood (3 or more RBC/HPF) that persists on a repeat test with no infection, period or exercise to explain it, especially if you are over 40, have ever smoked, or have painless bladder symptoms.
Blood in urine after an injury to the back or abdomen, or in anyone taking a blood thinner with lightheadedness, breathlessness or a fast pulse.

Frequently asked questions

What is a normal RBC count in urine?

Zero to 2 red blood cells per high-power field is normal on most reports, and some laboratories accept up to 4. Three or more RBC/HPF on a properly collected sample is the definition of microscopic hematuria used by the American Urological Association. A count of 3 to 10 with no symptoms is the lowest-risk band but still needs an explanation or a repeat test; counts above 25 per field move you into the highest evaluation tier regardless of age.

What does occult blood in urine mean?

'Occult' simply means hidden: blood detected chemically by the dipstick that you cannot see. The pad reacts to hemoglobin, so it is positive with intact red cells, with free hemoglobin from red cell breakdown in the bloodstream, and with myoglobin from muscle damage. Microscopy is used to tell these apart: red cells present means hematuria and the usual evaluation; a positive dipstick with no cells points to hemolysis or rhabdomyolysis and is investigated with blood tests instead.

Is trace blood in urine serious?

Usually not. Trace is the dipstick's lowest positive reading, around 5 to 10 red cells per microlitre, and it is common after exercise, in concentrated urine, around menstruation and with mild dehydration. It is also the reading most prone to false positives. The standard approach is to confirm with microscopy and repeat the test once temporary causes have passed. A trace result that keeps recurring and shows 3 or more cells per field on microscopy is treated as genuine microscopic hematuria.

What causes blood in urine but no infection?

When the culture is negative and there are no white cells, the common explanations are kidney stones, an enlarged prostate, recent strenuous exercise, menstrual contamination and glomerular kidney disease; the important one to exclude is a tumor of the bladder, kidney or urinary tract, especially in anyone over 40 or with a smoking history. Blood without infection is exactly the pattern that guidelines say should be evaluated with a creatinine, urine protein, cystoscopy and kidney imaging rather than watched.

Can exercise cause blood in urine?

Yes. Exercise-induced hematuria is well documented after running, cycling, swimming, rowing, boxing and contact sports, from bruising of the bladder wall, increased leakage through the kidney filters and red cell breakdown. It appears within hours and clears within 24 to 72 hours of rest. The rule used by clinicians is that blood still present on a sample taken 3 days after the last hard session is not from exercise and needs the normal evaluation.

Can blood thinners cause blood in urine?

Anticoagulants such as warfarin, apixaban and rivaroxaban, and antiplatelet drugs such as clopidogrel, make existing lesions bleed more readily, but they rarely cause bleeding from a healthy urinary tract. Studies of people on these drugs who developed hematuria found significant urological disease, including cancer, at about the same rate as in people not taking them. The drug is therefore not accepted as the explanation, and the evaluation is the same. Your INR or dose may also be checked.

What does blood in urine with no pain mean?

Painless blood is the pattern that most concerns clinicians, because bladder and kidney tumors typically bleed without pain, intermittently, and the urine may return to normal between episodes. Stones and infections usually hurt. Painless visible hematuria in someone over 50 has a cancer found in roughly one in five cases, so it is evaluated promptly with cystoscopy and imaging. Painless microscopic blood is more often benign (thin basement membrane disease, prostate enlargement, exercise), but is still investigated according to age and risk.

What foods and medicines turn urine red?

Beets (in about 10 to 14 percent of people, more if iron-deficient), blackberries, rhubarb, fava beans and red food dyes can color urine pink or red; rifampin, phenazopyridine (a urinary pain reliever), senna, some laxatives, chloroquine and nitrofurantoin color it orange, red or brown. In these cases the dipstick blood test is negative. Porphyria, hemoglobin from hemolysis and myoglobin from muscle breakdown also darken urine and are picked up by blood tests rather than microscopy.

References

Blood in urine. MedlinePlus, US National Library of Medicine (2023)View source
Urinalysis. MedlinePlus, US National Library of Medicine (2022)View source
Barocas DA, Boorjian SA, Alvarez RD, et al.. Microhematuria: AUA/SUFU guideline. Journal of Urology (2020)
Blood in urine (hematuria). Mayo Clinic (2024)View source
Hematuria in adults. National Institute of Diabetes and Digestive and Kidney Diseases (2023)View source
Isolated hematuria. Merck Manual Professional Version (2024)
Sharp VJ, Barnes KT, Erickson BA. Assessment of asymptomatic microscopic hematuria in adults. American Family Physician (2013)
Cohen RA, Brown RS. Microscopic hematuria. New England Journal of Medicine (2003)
Freedman ND, Silverman DT, Hollenbeck AR, Schatzkin A, Abnet CC. Association between smoking and risk of bladder cancer among men and women. JAMA (2011)
Borghi L, Meschi T, Amato F, Briganti A, Novarini A, Giannini A. Urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study. Journal of Urology (1996)
Williams G, Hahn D, Stephens JH, Craig JC, Hodson EM. Cranberries for preventing urinary tract infections. Cochrane Database of Systematic Reviews (2023)

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This page is educational and is not medical advice or a diagnosis. Lab results have to be interpreted together with your history, symptoms and other results by a clinician who knows you. Do not start or stop a supplement to change a lab value before the cause is known.