Blood in your urine, called hematuria, has many possible causes, and many of them are not serious, such as a urinary tract infection, a kidney stone or hard exercise. It can also be a sign of kidney disease or, less often, cancer of the bladder or kidney. That is why blood in your urine should always be checked by a doctor, even if it goes away on its own.
Key Takeaways
- Blood in urine can be visible, making urine pink, red or cola-colored, or microscopic, found only by a urine test.
- Common causes include urinary tract infections, kidney or bladder stones, an enlarged prostate and strenuous exercise.
- Some foods and medicines can turn urine red with no blood in it, so only a urine test can tell the difference.
- Blood together with protein in the urine, swelling, high blood pressure or reduced kidney function can point to the kidneys themselves.
- Get care right away if you pass clots, cannot urinate, or have a fever with pain in your side or back.
What Is the Difference Between Visible and Microscopic Blood in Urine?
Doctors describe two types. Gross hematuria means you can see the blood: your urine looks pink, red, brown or the color of tea or cola. Even a small amount of blood can change the color. It often causes no pain, though clots can hurt as they pass or if they block the flow of urine.
Microscopic hematuria means your urine looks normal, but a urine test finds red blood cells. It usually causes no symptoms and is often found at a routine checkup. Many healthy people have small amounts that clear up on their own, though not always, so the test may be repeated.
What Causes Blood in Your Urine?
Blood can come from anywhere along the urinary tract: the kidneys, the ureters (the tubes that carry urine to the bladder), the bladder or the urethra. Common causes include:
- Urinary tract infections, including bladder and kidney infections
- Kidney or bladder stones
- An enlarged prostate, also called benign prostatic hyperplasia (BPH)
- Strenuous exercise, such as long-distance running
- An injury, or a recent procedure on the urinary tract
- Kidney diseases that damage the kidneys’ filters, such as glomerulonephritis
- Some medicines, including blood thinners, aspirin and other pain relievers, and some antibiotics
Less commonly, blood in the urine is a sign of cancer of the bladder, kidney or prostate. Cleveland Clinic notes that about 3% of people who are evaluated for microscopic blood in the urine turn out to have cancer, with the risk depending on factors such as age and smoking. A cause, including a serious one, is more often found when the blood is visible. For infection warning signs, see early kidney infection symptoms, and for sharp side pain, see what kidney stones feel like.
Could Red Urine Be Something Other Than Blood?
Yes. Dark or red urine does not always mean blood. Foods such as beets, rhubarb and blackberries can change the color, and so can red food dyes. Some medicines can do it too, including ibuprofen, iron pills, nitrofurantoin, phenazopyridine and rifampin.
Because food, medicine and real bleeding can look alike, only a urine test can tell them apart. Do not stop a medicine because it might be changing your urine color. Talk to your doctor or pharmacist first.
Does Blood in Urine Mean Something Different for Women and Men?
For women, menstrual blood can get into a urine sample and make the test look positive when the urine itself has no blood. If you test positive during your period, you may be asked to repeat the test after it ends. Endometriosis can also cause blood in the urine, and vaginal bleeding can look as if it is coming from the urine.
Infections are the most common cause of microscopic blood, so ask whether you need a repeat urine test once one is treated. The American Urological Association notes that studies suggest women tend to be diagnosed with bladder cancer at later stages, partly because blood was put down to an infection. For men, an enlarged prostate is a common cause and prostate cancer a less common one, so a doctor may examine the prostate or order a PSA blood test. Blood from ejaculation can also be mistaken for blood in the urine.
How Do Doctors Find the Cause?
The first steps are usually questions about your health, a physical exam and a urinalysis (a urine test). A dipstick result is only a screen, so it is confirmed by looking at the urine under a microscope. Expect questions about your medicines, recent exercise, infections and foods that can change urine color.
Depending on the results, next steps may include:
- A urine culture to look for infection
- Blood tests, such as creatinine, to see how well your kidneys filter
- An ultrasound or CT scan of the kidneys and bladder
- Cystoscopy, in which a thin tube with a tiny camera looks inside the bladder and urethra
- A kidney biopsy, when a doctor suspects damage to the kidneys’ filters
This guide explains what kidney function test results mean.
When Does Blood in Urine Point to a Kidney Problem?
Bleeding can start in the kidneys’ tiny filters, called glomeruli, or elsewhere along the urinary tract. Signs that the filters may be involved include protein in the urine, swelling in the hands, ankles, legs or around the eyes, new or worsening high blood pressure, and blood tests showing reduced kidney function. The National Kidney Foundation notes that protein together with blood usually means a problem with the kidneys. Learn why protein in urine matters.
In general, bleeding from the filters is the area of a nephrologist (kidney specialist), while a urologist looks for structural problems such as stones, an enlarged prostate or a growth. When protein or reduced kidney function comes with the blood, both may be involved. Glomerulonephritis, which is inflammation of the filters, may be treated with medicines that reduce inflammation and medicines that help control blood pressure.
When Should You Get Medical Care for Blood in Your Urine?
Call 911 if bleeding comes with dizziness, confusion or feeling faint, which can be signs of shock.
Get care right away if you:
- Cannot urinate at all, or have severe pain in your belly
- Pass blood clots or a large amount of blood
- Have a fever, shaking chills, nausea or vomiting along with pain in your side, back or belly
- Have had microscopic blood before and can now see blood in your urine
If you cannot urinate or are passing clots and cannot reach your doctor quickly, go to an emergency room.
Make an appointment soon if:
- You saw blood in your urine, even once, and even if it went away
- A routine urine test found blood
- You also have burning, frequent or urgent urination, or weight loss you cannot explain
- Blood is still there after an infection was treated
Frequently Asked Questions
Is Blood in Urine Always Serious?
No. Many causes, such as an infection, a stone or hard exercise, clear up on their own or are easy to treat. But because a few causes are serious, every episode should be checked.
Can Exercise Cause Blood in Your Urine?
Yes. Strenuous exercise, such as long-distance running, is a known cause. Tell your doctor about recent hard workouts, but do not assume exercise is the reason without a test.
Can Blood Thinners Cause Blood in Your Urine?
Blood thinners can make bleeding from another cause heavier or longer, so doctors still look for that cause. The American Urological Association recommends the same evaluation whether or not you take a blood thinner. Do not stop or change one without talking to your doctor first.
What If the Blood Goes Away on Its Own?
The National Kidney Foundation notes that short episodes with no clear cause are usually not a problem and are more common in people under 35. After age 35, blood in the urine can be a sign of cancer even if it goes away, so tell your doctor either way.
What Happens If No Cause Is Found?
Sometimes tests find no reason. Your doctor may suggest repeating the urine test later, and if blood keeps showing up, yearly checkups help make sure kidney disease does not develop.
Does Diet Cause Blood in Urine?
According to the NIDDK, researchers have not found that diet causes or prevents hematuria. Foods like beets can turn urine red, but that is a change in color, not blood.
Talk to ANC About Blood in Your Urine
If a urine test shows blood along with protein, high blood pressure or changes in kidney function, a nephrologist can help find out whether your kidneys are involved. In most cases you need a referral from your primary care doctor, though it may depend on your insurance plan. Contact ANC or call 651-772-6251 to ask about an appointment.
Sources
- NIDDK: Hematuria (Blood in the Urine)
- National Kidney Foundation: Hematuria (Blood in the Urine) In Adults
- MedlinePlus: Urine – Bloody
- Cleveland Clinic: Microhematuria
- American Urological Association: Medical Student Curriculum: Hematuria
Medical Disclaimer
This article is for general educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your specific care and treatment options.
