A report that mentions hematuria simply means that red blood cells were found in a urine sample, and that finding alone does not tell you what caused them. The word covers two very different situations: urine you can see is red or brown, and urine that looks completely normal but contains red cells visible only under a microscope. Both deserve attention, but they lead to different next steps, and neither one is a diagnosis on its own.
In this article you will learn how laboratories define blood in urine, why a positive dipstick strip has to be confirmed by microscopy before anyone acts on it, which causes are common at different ages, how clinicians tell a kidney problem from a bladder or prostate problem, how the American Urological Association sorts patients into risk categories, and which symptoms mean you should not wait for a routine appointment.
What hematuria means on a urine test report
Laboratories report red blood cells in urine in two places. The chemical strip, or dipstick, gives a result such as negative, trace, small, moderate or large for blood. The microscopic examination gives an actual count, written as red blood cells per high-power field, often abbreviated RBC/HPF. A high-power field is simply one circular view through the microscope at high magnification, so the count is an average of what the technologist saw across several such views.
The threshold used across United States practice is three or more red blood cells per high-power field on a properly collected specimen. Below that, the finding is generally considered within normal limits. Everything about that sentence matters: the number, the microscope, and the words properly collected. You can compare the individual line items on your own report by reading our urine microscopy results guide.
Why the collection method changes the result
A clean-catch midstream sample reduces contamination from skin, the vaginal area or the foreskin. A sample collected during or just after a menstrual period can pick up blood that never came from the urinary tract at all. Samples that sit at room temperature for hours can also degrade, which is why laboratories prefer prompt processing. If a result looks surprising, repeating the test on a fresh, properly collected specimen is often the single most useful next step.
Gross hematuria versus microscopic hematuria
Gross hematuria means the blood is visible. It takes remarkably little blood to change the color of urine, so pink, red, tea-colored or cola-colored urine can come from a volume far smaller than most people imagine. That is reassuring in terms of blood loss, but it is not reassuring in terms of cause: visible blood carries a meaningfully higher chance of a serious underlying problem than a microscopic finding does, and it should always be evaluated.
Microscopic hematuria is invisible. It is usually discovered by accident, during a routine physical, an insurance screening, a pregnancy check or a workup for something else entirely. Most cases turn out to have a benign explanation, but a minority do not, and that is precisely why the finding is followed up rather than dismissed. Color changes that have nothing to do with blood are also common, and you can review them in our urine color chart explained for patients.
Why a positive dipstick has to be confirmed under the microscope
The dipstick pad for blood does not detect red blood cells directly. It detects the heme group, the iron-containing part of hemoglobin. Anything carrying heme will turn the pad positive, whether or not intact red cells are present. That makes the strip sensitive but not specific, and it produces a predictable list of misleading positives.
Free hemoglobin released when red cells break down inside the bloodstream will trigger the pad. So will myoglobin, the oxygen-carrying protein released from damaged muscle after a crush injury, a seizure or extreme exertion; if that possibility is raised, clinicians often check the corresponding blood protein described in our myoglobin blood test guide. Concentrated urine, certain antiseptic residues and some oxidizing cleaning agents can also skew the reading.
Then there are the causes that are not positives at all but simply look alarming. Beets, blackberries, rhubarb and food coloring can tint urine red without a single red cell being present. Rifampin, phenazopyridine, senna and some laxatives do the same. In every one of these situations the microscope settles the question, because it either finds red cells or it does not.
| What produced the result | Dipstick blood pad | Red cells under the microscope |
|---|---|---|
| True bleeding in the urinary tract | Positive | Present, three or more per high-power field |
| Free hemoglobin from red cell breakdown | Positive | Few or none |
| Myoglobin from muscle injury | Positive | None |
| Menstrual contamination of the sample | Positive | Present, but often with squamous cells |
| Beets, berries, rifampin, phenazopyridine | Negative | None |
| Vigorous exercise in the preceding days | Positive | Present, usually resolves on repeat testing |
What causes hematuria, and how likelihood shifts with age and sex
The list of possible causes is long, but the practical question is which ones are common in a person like you. Urinary tract infection is the single most frequent explanation in women of reproductive age, and it usually comes with burning, urgency or frequency; the pattern is described in our urinary tract infection symptoms and testing guide. Supporting dipstick findings often point the same way, which is why clinicians read the blood pad alongside the result explained in our leukocyte esterase test explanation.
Stones are the classic cause of blood with sudden, severe, one-sided flank pain that comes in waves and may radiate to the groin. Our kidney stones symptoms and treatment guide covers what typically follows that presentation. In men over fifty, an enlarged prostate is a frequent benign explanation, though it never removes the need to rule out other causes.
Causes that need to be excluded rather than assumed
Urothelial cancer of the bladder or upper urinary tract is uncommon in absolute terms but is the reason the whole evaluation exists. It is far more likely in people over fifty, in men, and above all in current or former smokers, and it very often presents as painless visible blood. Our bladder cancer signs and diagnosis guide sets out how that possibility is investigated. Kidney and prostate cancers can also bleed into the urine.
Kidney disease of the filtering units is a separate category. Immunoglobulin A nephropathy is the most common primary glomerular disease worldwide and classically produces visible blood a day or two after a sore throat or other infection; you can follow that thread in our Berger disease symptoms and testing guide. Inherited conditions such as thin basement membrane disease, sickle cell trait, and bleeding or clotting disorders round out the list.
Glomerular clues versus urologic clues
One of the most useful distinctions in the whole evaluation is where along the urinary tract the bleeding started. Blood arising in the glomeruli, the microscopic filters inside the kidney, behaves differently from blood arising in the ureters, bladder, prostate or urethra, and the urine itself carries the evidence.
Three findings point toward the kidney filters. Red blood cell casts are cylindrical molds of red cells formed inside the kidney tubules and are close to conclusive when present; our urinary casts results guide explains how they are reported. Dysmorphic red cells, meaning cells with distorted, irregular shapes acquired as they squeezed through the filter, point the same way. Significant protein alongside the blood is the third clue, and you can read how that is quantified in our urine protein test results guide. Kidney function is then assessed with the blood test covered in our serum creatinine results explanation.
Urologic bleeding looks different. The red cells are uniform and normally shaped, casts are absent, protein is minimal or explained by the blood itself, and visible clots may appear, since clots do not form inside the glomerulus. Pain patterns help too: colicky flank pain suggests a stone, burning on urination suggests infection, and painless visible blood in an older adult raises the priority of a cancer workup. When infection is suspected, the confirming test is discussed in our urine culture report guide.
How risk categories shape the evaluation of microscopic hematuria
Before 2020, everyone with microscopic hematuria in the United States tended to receive the same intensive workup, which meant a great deal of imaging and cystoscopy for people at very low risk. The American Urological Association and the Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction replaced that approach with a risk-stratified guideline, published in 2020 and amended in 2025. It sorts adults using age, sex, smoking history, the number of red cells seen, any history of visible blood, and other risk factors such as prior pelvic radiation or chemical exposure.
The table below summarizes the structure. It describes how clinicians typically approach each category; your own plan depends on your history and should be set with your clinician.
| Risk category | Who generally falls into it | What the evaluation usually involves |
|---|---|---|
| Low risk | Younger adults, never-smokers or minimal smoking history, a small number of red cells on a single test, no visible blood, no other risk factors | Shared decision to repeat the urinalysis within six months, or to proceed to cystoscopy and kidney ultrasound if the person prefers certainty |
| Intermediate risk | Middle-aged adults, a moderate smoking history, higher red cell counts, or persistent findings on repeat testing | Cystoscopy, a thin camera passed into the bladder, together with a kidney and bladder ultrasound |
| High risk | Older adults, a substantial smoking history, high red cell counts, any past episode of visible blood, or other established risk factors | Cystoscopy plus detailed cross-sectional imaging of the upper urinary tract, most often multiphase computed tomography urography |
| Any visible blood | Anyone with gross hematuria, at any age | Treated as a distinct situation requiring prompt evaluation rather than watchful waiting |
Why the results can be normal and still useful
A large share of evaluations find nothing. That outcome is not a wasted effort: it establishes a baseline, removes the most serious possibilities, and changes how any future finding is interpreted. Guidelines generally suggest a repeat urinalysis after a negative workup rather than indefinite testing, and a normal result on that repeat usually ends the process.
When to seek care right away
Most microscopic findings can be handled at a routine appointment. Some situations should not wait.
- Urine that is visibly red, pink, brown or cola-colored, even once, and even if it clears the next day.
- Blood with clots, or difficulty passing urine because of clots.
- Blood together with fever, chills, or pain in the flank or back, which can signal a kidney infection.
- Blood together with severe one-sided pain that comes in waves.
- Blood with an inability to urinate at all, which is a medical emergency.
- Blood after a fall, a blow to the abdomen or back, or a road accident.
- Blood alongside noticeable swelling of the legs or face, or a marked drop in the amount of urine, which points toward the kidney filters.
Being on a blood thinner does not explain away blood in urine. Anticoagulation can unmask bleeding from a lesion that was already there, so the evaluation proceeds in the same way.
Latest scientific advances
Research published in the last three years has focused less on new tests and more on whether the existing risk framework works in practice. According to PubMed, four findings stand out for patients.
The largest of them reviewed more than four thousand adults with microscopic hematuria who all received both imaging and cystoscopy, and asked whether the American Urological Association categories actually predicted what was found. They did, for cancers of the bladder and the drainage system: people in the high-risk group had a clearly higher rate of these tumors than people in the intermediate and low-risk groups, and the individual ingredients of the score, age, male sex, smoking history and the number of red cells, each carried weight. The same categories did not predict kidney tumors, which turned up at a similar rate regardless of risk group. The authors also noted that women aged seventy and older had a rate of bladder cancer high enough to argue for treating them as high risk. What this means for you is that the risk category is a good guide to how urgently the bladder needs to be examined, and a poorer guide to what imaging of the kidneys will show, which is one reason imaging is still part of the plan.
Two other studies looked at whether the guideline is actually followed. A review of primary care patients found that most people, including those in the highest risk group, never reached a urologist, and that only a minority of the evaluations that did happen matched what the guideline recommends. A separate chart review at a preventive health clinic found that fewer than half of adults with an elevated red cell count had a repeat urinalysis within six months. What this means for you is practical: if a result mentioned blood in your urine, it is worth confirming what the follow-up plan is rather than assuming one is already in motion. Both of these are retrospective reviews, meaning researchers looked back at existing records rather than following patients forward, so they describe what happened in particular clinics rather than proving what happens everywhere.
A fourth line of work concerns the kidney rather than the bladder. A 2026 review argued that in immunoglobulin A nephropathy, microscopic blood in the urine is an underused signal of active inflammation in the filters, and that following it alongside protein may describe disease activity better than protein alone. This is a review of accumulated evidence rather than a trial, so it reflects an emerging view rather than a settled change in practice. What this means for you is that when blood and protein appear together, a kidney specialist may pay attention to both over time rather than tracking protein by itself.
A broad clinical review published in 2025 pulled these threads together and made one point worth carrying away: visible blood, anemia, persistent symptoms or reduced kidney function are the features that should move an evaluation forward quickly, whatever the setting in which the blood was first noticed.
Glossary
| Term | Definition |
|---|---|
| Hematuria | Red blood cells present in the urine, whether visible to the eye or detectable only with a microscope. |
| High-power field (HPF) | One circular view through a microscope at high magnification. Red cells are counted per field and averaged across several fields. |
| Dipstick | A plastic strip with chemical pads dipped into urine. The blood pad reacts to heme, not to intact cells, so it can be positive without red cells being present. |
| Glomerulus | One of the roughly one million microscopic filters inside each kidney. Bleeding that starts here is called glomerular. |
| Red blood cell cast | A cylindrical mold of red cells formed inside a kidney tubule. Its presence points strongly to bleeding from the kidney filters. |
| Dysmorphic red cells | Red blood cells with distorted, irregular shapes acquired while passing through the glomerular filter. |
| Myoglobin | An oxygen-carrying protein from muscle. Released after muscle injury, it turns the dipstick blood pad positive without any red cells in the urine. |
| Cystoscopy | An examination in which a thin flexible camera is passed through the urethra to view the inside of the bladder. |
| Computed tomography urography | A CT scan taken in several phases with contrast dye, designed to show the kidneys, ureters and bladder in detail. |
| Urothelial carcinoma | Cancer arising from the lining of the bladder, ureters or renal pelvis. It is the main malignancy the evaluation is designed to detect. |
FAQ
Is hematuria dangerous on its own?
The finding itself does not harm you, and the amount of blood involved is almost never enough to cause anemia. What matters is the cause behind it. Most cases trace back to something benign such as an infection, a stone, an enlarged prostate or vigorous exercise. A minority reflect a condition that benefits greatly from early detection, which is why the finding is followed up rather than watched. Visible blood carries a higher chance of a significant cause than a microscopic finding and should always be reported to a clinician, even if it happens only once and clears on its own.
What is the most common cause of blood in urine in women?
In women before menopause, urinary tract infection is the most frequent explanation by a wide margin, usually accompanied by burning, urgency or lower abdominal discomfort. Contamination from menstrual bleeding is the other very common reason a sample tests positive, which is why clinicians often repeat the test outside the menstrual period. After menopause, the range of causes widens: thinning of the tissue around the urethra, stones and, less often, bladder cancer all become more relevant. Age changes the likely explanation more than sex does.
Does microscopic hematuria always mean cancer?
No, and in most people it does not. In large series of adults evaluated for microscopic blood in the urine, cancers of the bladder and drainage system are found in a small percentage of cases, and the rate is lowest in younger people with no smoking history. The evaluation exists because those cancers are highly treatable when caught early, not because they are the expected finding. Risk stratification is precisely the tool that keeps low-risk people from undergoing intensive testing they are unlikely to benefit from.
Can exercise cause blood in urine?
Yes. Intense or prolonged exertion, particularly running, can produce transient blood in the urine, and it typically clears within a few days of rest. Marching or running long distances can also break down red blood cells and damage muscle, which puts hemoglobin or myoglobin into the urine and turns the dipstick positive without red cells being present. Because exercise-related findings resolve, the usual approach is to repeat the urinalysis after several days without hard training rather than to start imaging immediately.
What happens when microscopic hematuria persists with no infection found?
Persistent red cells with a negative urine culture is the situation the risk-stratified guideline was written for. The next steps depend on your category: repeat testing for low risk, cystoscopy with ultrasound for intermediate risk, and cystoscopy with detailed cross-sectional imaging for high risk. If protein, red cell casts or misshapen red cells appear alongside the blood, the referral usually goes to a kidney specialist instead of a urologist, because those findings point to the filters rather than the drainage system.
Can blood in the urine go away on its own?
It often appears to. Blood from an infection stops once the infection is treated, blood from a passed stone stops once the stone passes, and exercise-related blood clears with rest. The difficulty is that blood from a tumor can also come and go, so an episode that resolved is not evidence that nothing was there. A single episode of visible blood is enough to warrant evaluation, regardless of whether the urine has since returned to normal.
Sources
- National Institute of Diabetes and Digestive and Kidney Diseases — Hematuria (Blood in the Urine) — NIDDK, National Institutes of Health, reviewed 2022 — niddk.nih.gov
- Cleveland Clinic — Blood in Urine (Hematuria): Causes, Diagnosis and Treatment — Cleveland Clinic Health Library, reviewed 2025 — my.clevelandclinic.org
- MedlinePlus, National Library of Medicine — Urine, bloody — MedlinePlus Medical Encyclopedia, reviewed 2025 — medlineplus.gov
- American Urological Association and SUFU — Microhematuria: AUA/SUFU Guideline (2020, amended 2025) — American Urological Association, 2025 — auanet.org
- Udedibia E, Solosky K, Macdonald EJ, et al. — Critical Analysis of the AUA 2020/2025 Microscopic Hematuria Guidelines to Predict Urothelial but Not Renal Cortical Neoplasms — The Journal of Urology, 2025 — doi.org/10.1097/JU.0000000000004854
- An C, Jeong J, Chiu C, et al. — Risk stratification and diagnostic evaluation of patients found to have microscopic hematuria by their primary care providers — Journal of General and Family Medicine, 2024 — doi.org/10.1002/jgf2.740
- Munroe D, O’Keefe J, Wang D, Moore MA — Evaluation of the 2020 American Urological Association Microscopic Hematuria Guidelines in Clinical Practice: Retrospective Chart Review Analysis — JMIR Formative Research, 2025 — doi.org/10.2196/75929
- Floege J, Fervenza FC, Coppo R — Microscopic hematuria in IgA nephropathy: a biomarker of disease activity — Clinical Kidney Journal, 2026 — doi.org/10.1093/ckj/sfag003
- Szymkiewicz S — Clinical Significance, Differential Diagnosis and Initial Management of Hematuria in Emergency and Outpatient Settings — Cureus, 2025 — doi.org/10.7759/cureus.91639
Further reading
- Compare the finding that signals white cells rather than red ones by reading our pyuria test results guide.
- Check the dipstick pad that points toward bacterial infection with our urine nitrite results explanation.
- Track early kidney damage using the measurement described in our albumin to creatinine ratio guide.
- Explore the long-term condition that can follow persistent kidney injury in our chronic kidney disease overview.
- Review the male urologic cancer that can also bleed into the urinary tract with our prostate cancer symptoms and PSA testing guide.
Understand your lab results with BloodSense
A urinalysis rarely arrives with an explanation attached, and the line that mentions blood sits next to protein, leukocyte esterase, nitrite and specific gravity, each of which shifts what the others mean. BloodSense reads those values together and puts them into plain language, so you can see whether the picture leans toward infection, a stone or something that deserves a specialist appointment. It helps you understand what your report says and prepare better questions; it does not diagnose you and does not replace your clinician.
