Red blood cells (RBCs) can be present in your urine, whether you see pink in the toilet bowl or not. Having RBCs in your urine is called hematuria.
There are two types of hematuria:
- Gross hematuria means blood is visible in your urine.
- Microscopic hematuria involves RBCs that can only be seen under a microscope.
RBCs aren’t typically found in urine. Their presence is usually a sign of an underlying health issue, such as an infection or irritation of the tissues of your urinary tract.
Doctors will usually test for RBCs during a urinalysis. For this test, a person provides a urine sample for testing.
Ideally, this urine sample will be a clean catch sample. Providing a clean catch sample involves cleaning your genital area and allowing a small amount of urine to go into a toilet before putting the rest in a sample cup. This helps ensure the urine sample doesn’t contain any contaminants.
The sample is then sent to a laboratory for testing. Sometimes, a doctor will use a dipstick to quickly test a urine sample for the presence of RBCs before sending the sample off to a laboratory.
The dipstick looks like a piece of paper, but it contains chemicals that’ll change the color of the paper if it comes into contact with RBCs. This won’t give a precise measurement, but it can help narrow down a diagnosis or rule out certain conditions.
RBCs aren’t usually present in urine, so there isn’t a normal range.
However, if you’re menstruating when you provide a urine sample, your urine will likely contain RBCs. This isn’t cause for concern, but make sure to tell your doctor before providing the sample that you’re menstruating.
Some of the causes of high RBCs in urine may be acute. This means they’re temporary conditions that only last for a short period of time.
Some acute causes of RBCs in urine include:
- Infections. An infection in your urinary tract, bladder, kidneys, or prostate can cause inflammation and irritation that lead to RBCs appearing in urine.
- Sexual activity. Recent sexual activity can cause irritation of the tissues around the urinary tract.
- Vigorous exercise. Recent strenuous activity can also inflame the tissues of the urinary tract.
- Kidney or bladder stones. The minerals in your urine can crystalize and cause stones that adhere to the kidney or bladder walls. They won’t cause you any pain unless they break loose and pass through the urinary tract, which is very painful. The irritation from the stones can cause blood in the urine, either microscopic or large amounts.
Some chronic (long-term) conditions that can cause RBCs in urine include:
- Hemophilia. This is a bleeding disorder that makes it harder for a person’s blood to clot. This results in easy bleeding.
- Polycystic kidney disease. This condition involves cysts growing on the kidneys.
- Sickle cell disease. This disease causes irregularly shaped RBCs.
- Viral hepatitis. Viral infections can inflame the liver and cause blood in urine.
- Bladder or kidney cancer. Both of these can sometimes cause RBCs in urine.
Some medications can also cause the presence of RBCs in urine. Examples include:
- blood thinners
Before giving a urine sample, make sure to tell your doctor about all medications you take, including any over-the-counter (OTC) ones.
If your urine sample tests positive for RBCs, your doctor will likely start by going over the other results of the test. For example, if your urine also contained certain bacteria or white blood cells, you may have an infection.
Depending on your other symptoms and medical history, you may need more invasive tests. For example, a cystoscopy involves inserting a small camera into your urinary tract to get a better view of your bladder.
Your doctor may also do a tissue biopsy on your bladder or kidneys to check for any signs of cancer. This involves taking small tissue samples from these organs and looking at them under a microscope.
Several things can cause RBCs to show up in your urine, from heavy exercise to bleeding disorders. Make sure to tell your doctor about any other symptoms you have as well as any prescription or OTC medications you take.
If your urine sample tests positive for RBCs, your doctor will likely conduct a few additional tests to help determine the underlying cause.