Blood in urine can be visible to the naked eye or completely invisible. When you can see it, your urine looks pink, red, or brown (sometimes described as cola-colored). When you can’t see it, called microscopic hematuria, the only way to know is through a lab test. It takes a surprisingly small amount of blood to change the color of urine, so even a faint pink tinge is worth paying attention to.
What Visible Blood in Urine Looks Like
The color depends on how much blood is present and how concentrated your urine is. A small amount of blood typically gives urine a light pink shade. More blood turns it red or dark brown. Some people describe it as looking like tea or cola. The color can also shift depending on when in your urine stream the blood appears: blood at the very beginning suggests a source in the urethra, while blood throughout points to the bladder or kidneys.
You might also notice small clots, which can look like dark specks or stringy fragments. Clots aren’t always present, but when they are, they’re hard to miss. Bleeding is sometimes painless and sometimes accompanied by burning, urgency, or flank pain, depending on the cause.
Things That Look Like Blood but Aren’t
Before assuming the worst, consider what you’ve eaten or taken recently. Beets are one of the most common culprits. A condition called beeturia can turn urine pink or red within hours of eating them. Blackberries, rhubarb, and foods with red dye 40 can do the same.
Several medications also change urine color. Iron supplements can darken it. Certain antibiotics and a common bladder pain reliever (phenazopyridine, sold as AZO or Pyridium) turn urine bright orange or reddish. Even a synthetic form of vitamin B12 can cause discoloration. If you recently started a new medication or ate something unusual, that’s worth considering before panicking.
Microscopic Blood You Can’t See
Microscopic hematuria produces no visible change in your urine and causes no symptoms on its own. It’s typically caught during a routine urinalysis for something else entirely. Clinically, it’s defined as three or more red blood cells per high-power field under a microscope. Fewer than that is generally considered insignificant and doesn’t require further investigation.
This is actually the more common form of blood in urine, and it’s found incidentally in a significant number of adults during routine physicals. Most of the time it turns out to be harmless, but because it can occasionally signal kidney disease or early bladder problems, doctors usually follow up with additional testing if the count is consistently elevated.
Can You Test at Home?
Over-the-counter urine dipstick strips are available at most pharmacies and can detect blood. They work by reacting to hemoglobin, the protein inside red blood cells. Their specificity ranges from about 65% to 99%, which means they catch most true cases but also produce false positives. Concentrated urine, menstrual contamination, and even a hard workout can trigger a positive result when no actual bleeding is occurring.
A positive dipstick alone doesn’t confirm blood in urine. It needs to be followed by a microscopic urinalysis, where a lab technician actually looks at a urine sample under a microscope and counts the red blood cells. This is the standard that determines whether further evaluation is needed.
Common Causes
Urinary tract infections are one of the most frequent reasons for blood in urine, especially in women. The infection inflames the bladder lining, which can bleed enough to turn urine pink or red. You’ll usually also notice burning during urination, frequent urges to go, and sometimes cloudy or strong-smelling urine. Once the infection is treated, the bleeding stops.
Kidney stones are another major cause. As a stone moves through the urinary tract, it scrapes the lining and causes bleeding. This type of hematuria often comes with intense, wave-like pain in the back or side. Vigorous exercise can also trigger temporary blood in urine, particularly in endurance athletes like long-distance runners. This type typically resolves on its own within 48 to 72 hours. If it doesn’t clear in that window, further evaluation is recommended.
Other causes include enlarged prostate in older men, kidney disease, and less commonly, bladder or kidney cancer. Painless visible blood in urine, particularly in adults over 50, is taken more seriously because it has a higher association with urinary tract cancers. That doesn’t mean it’s the most likely explanation, but it’s the reason doctors don’t dismiss it.
What Happens During a Medical Evaluation
If blood is confirmed in your urine, the next step depends on your age, symptoms, and risk factors. For a young woman with a straightforward urinary tract infection whose bleeding clears completely after treatment, imaging tests are usually unnecessary.
For everyone else, doctors typically want to look at both the upper urinary tract (kidneys and ureters) and the lower tract (bladder and urethra). A CT scan is the most sensitive tool for evaluating the kidneys, picking up small stones and tumors that other methods can miss. Ultrasound is a radiation-free alternative used for children, pregnant women, or people who can’t receive CT contrast dye.
For the bladder, imaging alone isn’t enough. A cystoscopy, where a thin camera is inserted through the urethra to directly inspect the bladder lining, is the standard because no imaging technique reliably catches small bladder lesions. Virtual cystoscopy using CT images exists but misses small abnormalities and can’t evaluate the urethra, so it hasn’t replaced the real thing.
When Bleeding Matters More
Certain patterns raise more concern than others. Painless blood in urine that appears without an obvious trigger like infection or exercise deserves prompt evaluation, especially if you’re over 40. A history of smoking significantly increases the risk of bladder cancer, making unexplained hematuria in smokers or former smokers particularly important to investigate.
Blood that persists across multiple urine tests, comes with unexplained weight loss, or is accompanied by difficulty urinating also warrants a more thorough workup. On the other hand, a single episode of microscopic hematuria in someone under 35 with no risk factors is far less likely to represent something serious, though it’s still worth confirming with a repeat test.