Blood in Your Urine? When It Might Be a Kidney Stone
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By David Shusterman, MD · May 20, 2026
Seeing blood in your urine is alarming, and it should never be ignored — but it also isn't always the emergency it feels like. One of the most common causes is a kidney stone scraping the lining of the urinary tract as it moves.
Why stones cause bleeding
A stone has rough, crystalline edges. As it travels from the kidney down the ureter, it can irritate or nick the delicate lining, releasing a small amount of blood into the urine. Sometimes that blood is visible (pink, red, or tea-colored urine); sometimes it's microscopic and only picked up on a urine test.
What else it could be
Blood in the urine can also come from infections, an enlarged prostate, vigorous exercise, certain medications, and — less commonly — conditions that genuinely need ruling out. That's exactly why visible or persistent blood in the urine is worth a proper evaluation rather than a wait-and-see at home.
What to do
If you see blood in your urine, get it checked. If it comes with fever, chills, an inability to urinate, or severe pain, treat that as urgent and seek emergency care. Otherwise, a prompt evaluation — including imaging if a stone is suspected — sorts out the cause and tells you whether a stone is present, how big it is, and where.
Concerned about a kidney stone?
If any of this sounds like your situation, a prompt evaluation can tell you exactly what's going on.
UNDERSTAND YOUR CARE
What blood in the urine can—and cannot—tell us
Urine color cannot identify where bleeding started. Blood may come from the kidneys, ureters, bladder, prostate or urethra, so the evaluation follows the evidence and your individual risk.
Confirm the finding and its context
A dipstick result, red urine and red blood cells seen under a microscope are related findings, but they are not interchangeable. Foods and medicines can alter color, and menstrual or other bleeding can contaminate a sample. A properly collected urine specimen helps establish what is actually present.
Tell the clinician whether blood was visible, whether clots appeared, whether it happened more than once, and whether pain, burning or fever accompanied it. Smoking history, prior treatments, medicines and kidney history can affect the work-up. Bring previous urine results or imaging when available.
A resolved episode still deserves an explanation
Bleeding can stop even when its cause remains. The absence of pain does not establish that it is harmless. Conversely, blood does not automatically mean cancer: stones, infection, prostate conditions and kidney disease are among the possible explanations.
Visible bleeding and microscopic blood may lead to different risk-based pathways. Depending on the findings, evaluation can include repeat urine testing, kidney assessment, imaging and cystoscopy. Cystoscopy examines the bladder and urethral lining directly; imaging answers different questions about the upper urinary tract. If infection is treated, ask whether a repeat urine test is needed to confirm that blood cleared. A clear follow-up plan is part of the evaluation, including what happens if bleeding returns.
Questions to bring to your visit
- Has true urinary blood been confirmed, and could contamination affect the sample?
- Which tests fit my risk and what question does each answer?
- What follow-up is needed if the initial evaluation is reassuring?
When to seek care: Seek emergency care for inability to urinate with clots, heavy bleeding with weakness or faintness, or bleeding accompanied by severe illness. Visible blood warrants prompt medical contact even if it stops.
Explanation adapted from A Urology Consult in a Book by David Shusterman, MD, chapter 10, “Blood In The Urine.” Original illustration reproduced from the book. NIDDK: blood in the urine.