It’s one of life’s bigger freak-outs: You go to the bathroom and your pee is bright red—and not because you’ve eaten beets. Or the doctor’s office calls you up to tell you there was blood in your urine sample. A session with Dr. Google probably won’t ease your anxieties when you discover blood in the urine is a sign of bladder cancer.
We’re not going to lie: Blood in your pee means something is wrong, and you need to check it out pronto. But it’s actually pretty common—nearly a third of adults will experience it, according to the stats—and there are a host of reasons why it happens, many of them issues that can be cleared up fairly easily.
Your primary doctor or a urologist will be the one to give you a diagnosis. But this guide will help you figure out the reasons why there might be blood in your urine—and what tests you should ask for. First, though, you need to know about the two types of blood that can appear in your urine.
We went to some of the nation’s top experts in bladder cancer to bring you the most up-to-date information possible.
Philippe Spiess, M.D.Genitourinary Oncologist and Assistant Chief of Surgical Services
Gary Steinberg, M.D.Urologic Oncologist and Bladder Cancer Surgeon
William Tabayoyong, M.D.Assistant Professor of Urology and a Urologic Oncologist
How Doctors Classify Blood in Urine
Physicians call blood in your urine hematuria. Gross hematuria (yeah, bloody pee is disgusting but that’s not what they mean) is blood that shows up in the toilet or after you wipe. It doesn’t take much, either. One milliliter of blood—about a fifth of a teaspoon—is enough to turn your pee red or pink. Either way, if you see something, even once, make an appointment.
Then there’s microscopic hematuria, which is what it sounds like—blood that’s only visible under a microscope. Anything over three or four red blood cells is considered abnormal. Just don’t be fooled by the amount. Doctors take microscopic levels just as seriously as they do gross hematuria because both types can be early signs of bladder or kidney cancer, especially if you have the risk factors for either cancer: you’re a smoker, past or present, you’re over 51, and you are male.
In a study done on 2,000 patients with microscopic levels of blood, researchers from Columbia University found that 1.2% had bladder cancer. So no, not huge numbers of people, but we’d consider them lucky: All were diagnosed when the cancer was in its earliest and most treatable stages. Moral? Always get any blood in your urine checked out.
What Causes Blood in Urine (When It’s Not Cancer)?
There are many reasons why you’re peeing blood, and some of them are really common. Here are some of the top reasons:
You Have a Urinary Tract Infection (UTI)
Bacteria, especially E. coli, are the culprits in UTIs, multiplying in the bladder or urethra and causing irritation and infection. They’re more common in women than men (about 60% of women vs. 12% of men will get at least one UTI during their life), thanks to the relatively short distance the bacteria have to travel from a woman’s anus to the urethra and up to the bladder. Bladder infections are known as cystitis.
Other UTI symptoms:
You have to go more often and/or only pee a few drops.
It hurts or burns when you urinate.
You have pain or discomfort in your lower abdomen or back.
UTI tests and treatments: The only way to really rule out a UTI is to get a urine test or culture that looks for bacteria. Then your provider will give you antibiotics. UTIs can come back, and if you have more than three a year, talk to your doctor. You might be put on long-term antibiotics or given further tests to figure out the reason for the infections.
Good to know: Because older women are prone to UTIs and they don’t develop bladder cancer at the same rate as men, some doctors will prescribe antibiotics without getting a urine sample or they’ll keep prescribing meds because they think the infection has come back. There’s a danger in doing that, say bladder cancer experts: Postponing bladder-cancer screening tests is a big reason women are diagnosed at later stages and die from the disease more often than men. So always insist on a urine culture and if there’s no bacteria, ask for further tests, especially if you are or were a smoker.
You Have a Kidney Infection
If left untreated, bacteria can travel from your bladder to one or both of your kidneys and cause an infection. Or something might be blocking the kidneys (like kidney stones or an enlarged prostate), causing urine to back up into them. If not caught early, the bacteria causing the infection could get into your bloodstream, which can be deadly.
Other kidney infection symptoms:
You have pain in the upper back or side.
You have a fever and/or chills.
You’re urinating more often.
Your urine is smelly or cloudy.
Kidney infection tests and treatment: Doctors will check your urine for bacteria and perhaps run a blood test to check if the bacteria have gotten into your bloodstream. They might also take an ultrasound or CT-scan of your kidneys to check for stones or other obstructions; and they may order a special x-ray that checks your bladder when it’s full as well as when you are urinating. If a kidney infection is confirmed, you’re treated with antibiotics, usually for two weeks. If the infection still hasn’t gone away, you might go into the hospital to get the drugs via an IV.
You Have a Kidney Stone
Sometimes the calcium, uric acid, salt, and other minerals in your urine can form hard clumps and collect in your kidneys. Occasionally, these stones cause no symptoms at all. But other times they travel down the tubes connecting the kidneys to the bladder (called ureters) and get stuck there, causing the kidney to swell. Or they can travel down to the bladder where they remain until you pee them out, which can be painful, too.
Other kidney stone symptoms:
Sharp cramps in the back or sides that move downward toward your groin (as the stone tries to pass through your body) or pain that comes in waves. The pain can range from unbearable to tolerable.
An urgent and/or constant need to pee
A burning sensation when you urinate
Fever or chills: If you have a fever, blood in the urine, and pain that’s so severe you can’t get comfortable go to the ER.
Kidney stone tests and treatment: Imaging tests like an ultrasound or CT-scan can tell your provider how big the stone is and where it’s located, and that can determine treatment. You may be given the option to pass the stone on your own if it’s small enough and you can tolerate the pain, even if it takes a few weeks. Or your doctor may give you Flomax (tamsulosin) that relaxes the ureter so it’s easier for stones to pass through. If the stones are very big or blocking your kidneys, you may need surgery.
You Injured Your Kidneys
About 3.5% of all trauma patients injure their kidneys—mostly through falls and car accidents as well as stabbings and shootings. Any fall or accident that affects the back, sides, ribs, and upper abdomen can damage your kidneys. Sometimes there’s only slight bleeding, which shows up in microscopic levels.
Other symptoms of kidney injury: Bruises on your back and sides
Test and treatment for kidney injury: A CT scan is the best way to evaluate any damage. Depending on how serious the accident was, you’ll be monitored for further bleeding. In some cases, you may need surgery to control the bleeding or to remove the organ completely.
You Worked Out Way Too Hard
Although rare, really strenuous exercise—think marathons—can cause red-blood and muscle cells to break down and exit your body when you pee. Officially called rhabdomyolysis, it can also occur when your body temperature gets too high (like if you worked out in the hot, hot sun). This is more common among men than women, and it can be very serious if not treated.
Other symptoms: Muscle swelling, weakness, and tenderness; decreased urination
Tests and treatment: If the blood doesn’t clear up on its own within a day, or comes back even if you haven’t had an extra-hard session at the gym, call your provider. There may be some sort of underlying issue, like kidney disease.
You’re Taking Blood-thinning Medications
You don’t have to be on a blood thinner to have blood visibly show up in your urine. Even aspirin, nonsteroidal anti-inflammatory pain relievers (NSAIDs) like ibuprofen, and antibiotics can produce that effect. Same goes for many naturopathic, herbal, and homeopathic remedies that impact blood clotting. This is rare, though, so if it happens, call your doctor. It could be you have some underlying issue (a UTI, kidney disease) that needs to be checked out.
You Have Kidney Disease
There are two conditions that can produce blood in the urine: polycystic kidney disease (PKD) and glomerulonephritis. PKD causes your kidneys to produce many large, fluid-filled cysts. Left untreated, the cysts crowd out normal tissue, leading to kidney damage. Glomerulonephritis harms the kidneys’ blood-filtering system. When the kidneys don’t work, your body can’t get rid of waste and fluid. If you don’t treat the disease, your kidneys will eventually fail.
A puffy face and swollen ankles (from fluid retention)
High blood pressure
Protein in your urine
High blood pressure
Pain in the back or side
A swollen belly
Tests and treatment for kidney disease: Ultrasound is the quickest way to discover if you have PKD. For glomerulonephritis, a urinalysis can spot protein as well as blood cells in your pee and blood tests to check your GFR number, which is the formula used to see how well the kidneys are working. While one medication has been approved to treat a type of inherited PKD, lifestyle changes like drinking fluids, weight loss, and controlling your blood pressure are the ways to slow the damage. The same is true for chronic glomerulonephritis, which can be managed by taking diuretics, eating less salt, and monitoring your blood pressure.
You Have Benign Tumors
Non-cancerous tumors can form in the bladder and kidney and cause blood in the urine. Benign bladder tumors are rare. They’re more likely to grow in the kidneys.
Other benign tumor symptoms: They rarely cause symptoms, but if they do, kidney tumors can cause pain in your lower back. Benign bladder tumors can sometimes mimic the symptoms of a UTI.
Tests and treatment for benign tumors: The only way to tell whether a tumor is malignant or benign is to do a biopsy. Then the treatment depends on you and your doctor.
There’s No Reason for the Blood
For the majority of folks younger than age 50, there’s usually no underlying issue causing microscopic levels of blood (as long as you don’t have other symptoms). For this reason, the American College of Obstetricians and Gynecologists (ACOG) does not recommended extensive cancer screening in women ages 35 to 50 who’ve never smoked, never had visible blood in their urine, and have fewer than 25 red blood cells in a urine sample. Their risk is a mere 0.5%. This isn’t the case for women who have more than 25 RBCs, are over 51, have a history of smoking, or have had gross hematuria.
Blood in Urine: Women vs. Men
Men and women each have unique possible causes of finding red blood cells in their pee.
Females: You’re Postmenopausal
Who knew? Your urinary tract is just as affected as the rest of you when estrogen levels drop and you stop having your period. And thanks to the thinning walls of your vagina (also affected), red blood cells (RBC) can show up in your pee at microscopic levels. This happens to roughly one in five post-menopausal women.
Other symptoms: None really—this only applies to RBC that are invisible to the naked eye. If you are peeing out visible blood, that’s a different issue.
Tests and treatment: Red blood cells are usually detected after a routine urine sample or one for a UTI. If the RBC count is over four, guidelines call for these women to be screened for cancer, either through an imaging test or a probe. But a Duke University study of nearly 240 women found that the rate of cancer was quite low—about 1.4%, not surprising since men are more likely to get bladder and kidney cancers. The researchers recommendation: Give post-menopausal women with microscopic blood levels a gynecological exam first to check for atrophy. If that’s ruled out (as well as infections) then you can get screened for cancer. You can talk to your GYN about estrogen creams or lubricants to help vaginal atrophy, which can make sex painful and make your vagina itchy and uncomfortable.
Males: You Have an Enlarged Prostate
Men aren’t off the hook either as they age. About 50% of men between 51 and 60 have an enlarged prostate, and those numbers go up with every decade until 90% do at age 80. The prostate has a lot of veins, and as it gets bigger, it presses against the urethra and blocks it off.
Other symptoms of an enlarged prostate:
You get up frequently in the night to pee.
You have a weak stream.
You have to wait a while before the urine comes out (called hesitancy).
You never feel as if you fully empty your bladder.
Prostate tests and treatment: A rectal exam can tell your provider how big your prostate is getting. Other tests can include urinalysis (to check for infection) and a PSA blood test, which checks for a special protein called PSA made by prostate cells. Anything can up your PSA count, including prostate cancer as well as an enlarged prostate. If your provider suspects prostate cancer, you may undergo a transrectal ultrasound to check for tumors. If you “just” have an enlarged prostate, your provider might suggest pelvic-floor exercises to strengthen your bladder, restricting the amount of caffeinated drinks, medications like alpha blockers (to relax the urinary tract and bladder), and, in really severe cases, surgery.
When Blood in Your Urine Means Bladder or Kidney Cancer
If doctors have ruled out the other reasons, they’ll want to check for bladder or kidney cancer if you have the risk factors. Besides a history of smoking and age, they include:
Having a family history of bladder or kidney cancer
You’re obese (especially for kidney cancer)
For bladder cancer, one of the main signs is painless blood you can see. In a study of nearly 1,200 people with gross hematuria, urologists at Weill Cornell Medical College in New York City found that 31% of them had bladder cancer. But that number more than doubled (64%) for those current or former smokers who were older than 65. Sounds scary, right? But one thing that’s good to know is that the majority of bladder cancer patients are diagnosed before the tumors have spread too far into the bladder.
The early stages of kidney cancer usually don’t produce symptoms, but larger tumors will cause blood in the urine.
Other symptoms of cancer: Very rarely, bladder cancer symptoms mimic a UTI—burning and a frequent need to go. People with kidney cancer might have a pain on one side of their lower back, weight loss, fatigue, anemia, and a fever.
Tests and treatment: Have your primary doctor send you to a urologist for testing. A urologist will do imaging tests of your bladder, kidneys, and reproductive organs to check for spots or masses. For kidney cancer, doctors order blood tests to check for anemia and how well the kidneys are working. For bladder cancer, the M.D. will also look inside your bladder for tumors with a probe inserted through your urethra in a test called a cystoscopy. If the urologist finds a tumor, it’ll be biopsied and removed, most likely in the hospital. Depending on the results for either cancer, you and the urologist can come up with a treatment plan.
Even if you do have cancer, remember this statistic: If the tumor is just confined to the inner lining of the bladder or inside the kidney(s), your five-year-survival rate (or the number of cancer patients who are still alive after five years) is over 90%: Specifically? It’s 93% for kidney cancer and 95% for bladder cancer.
What are the odds I have cancer if there’s blood in my urine?
Well, it depends on your risk factors and the type of blood. But for most people under age 50, the chance of having either bladder or kidney cancer if you have microscopic levels of blood is about 3%. If you have risk factors, it’s about 25%. Blood you can see ups your chances of bladder cancer to 31%.
What tests should I ask for if I see blood in my urine?
The first step is to get a urine culture to check for bacteria in case you have a UTI or kidney infection. If it comes out negative and you’re older than 50, ask to be referred to a urologist. A urologist can evaluate your risk factors and see if you need more tests, like CT scans, blood tests, and a cystoscopy.
Why do UTIs cause blood in the urine?
Bacteria get into your bladder and multiply, inflaming the lining and causing it to bleed, which then gets into your pee.
Is blood in my urine dangerous?
It’s a sign that something is wrong, so you definitely want to get it checked out. Chances are, it’s either an infection or a kidney stone, not cancer.
Gross Hematuria and Cancer Statistics:World Journal of Urology. (2012). “Accurate Risk Assessment of Patients with Asymptomatic Hematuria for the Presence of Bladder Cancer.” ncbi.nlm.nih.gov/pmc/articles/PMC4004026/
While there is no evidence that a particular diet can reduce your risk, results from multiple studies show a link between bladder cancer and what we eat. So it wouldn’t hurt to stock up on yogurt, green tea, and oranges — and also, they’re delicious, so why wouldn’t you want to?