Red blood cells (RBC) can be present in urine even when they are not visible to a person. The medical term for RBC in the urine is hematuria.
There are two types of hematuria. One is called "gross hematuria," which occurs when a person can see the blood in their urine. The other type is "microscopic hematuria," wherein a person cannot see the blood in their urine, despite the fact that RBC are present.
However, RBC in the urine is usually a symptom of an underlying health condition. A doctor will typically test for RBC content during a urine test. They will then use the results to help determine what the next course of action should be.
Keep reading for more information on what RBC in the urine might mean, normal and abnormal ranges, and typical test results.
There are several potential causes of RBC in the urine, including:
- urinary tract infections (UTIs)
- kidney or bladder infections
- kidney stones
- vigorous exercise, which requires the body to send lots of blood to the muscles
- rhabdomyolysis, wherein severely damaged muscles cause substances from within the muscles to leak into the blood
- sexual intercourse that causes irritated tissue
Also, some medications can cause RBC in the urine. Some potential medications that may lead to RBC in the urine include:
There are also some chronic conditions that can lead to RBC in the urine. These include:
- sickle cell disease
- hemophilia, which makes blood clotting harder for some people's bodies
- polycystic kidney disease, which occurs when cysts form on the kidneys
- bladder or kidney cancer
- enlarged prostate
In some cases, a person may not experience any additional symptoms of RBC in the urine. However, some conditions in the list above can also cause pain, swelling, or a fever.
Other symptoms a person might notice if they have a condition causing RBC in the urine include:
- urine that looks pink, red, or the color of tea
- a frequent need to urinate
- pain or difficulty urinating
- pain in the stomach or back
- swollen feet, legs, or ankles
If a person notices blood in their urine, they should talk to their doctor as soon as possible.
In most cases, a doctor will discover RBC in the urine during a urinalysis. A urinalysis checks for several key health indicators following the delivery of a urine sample.
The ideal sample uses the "clean catch" method. The clean catch method involves starting the flow of urine and placing the collection cup into the flow midstream. This helps remove any potential contamination from bacteria or other substances that may be near the genitals.
In some cases, a doctor can use a simple dipstick to test the urine for blood. A dipstick is a piece of paper with chemicals on it. These chemicals react with different substances that may be present in the urine. In the case of looking for RBC, a dipstick will turn a different color if RBC is present.
After this, the doctor will send the sample to a laboratory for further testing. The laboratory staff can provide more information about the amount of RBC, as well as any other substances that could indicate an underlying condition, in the urine.
A very small amount of RBC may be present in a normal urine sample. In fact, according to the Icahn School of Medicine at Mount Sinai in New York, the normal range for RBC in the urine is up to four RBC per high power field.
However, different laboratories may have different ranges for a "normal" result. For this reason, a person may wish to talk to their doctor about what their test results mean.
An abnormal range can indicate any one of a number of potential issues. Some of the possible conditions include:
- kidney or other urinary tract problems, such as an infection, a tumor, or stones
- problems with the prostate
- bladder or kidney cancer
If a test reveals that a person has RBC in their urine, a doctor will likely run additional tests. For example, they might want to carry out:
- blood tests
- CT or MRI scans, to examine the kidneys and urinary tract
- a biopsy of the kidneys
- cystoscopy, wherein they will use a thin, flexible tool to examine the urinary tract
A doctor will also ask about any other symptoms a person is experiencing that may indicate an underlying health condition. A person should discuss their concerns with their doctor before providing a urine sample.
It is also important to note that sometimes, a test may generate a false reading. This can occur if a person takes the test while menstruating, for example. In this case, blood can get into the urine sample and cause a false reading.
Pregnant women should not see blood in their urine. If they do, they should let their healthcare team know right away. If they provide a urine sample with blood in it, a doctor will try to diagnose and treat any underlying conditions.
Since UTIs are common during pregnancy, the most likely cause of blood in the urine is a UTI.
However, a doctor may run tests and ask questions to rule out other potential issues.
RBC in the urine can indicate that there is a problem with the urinary tract. If a person discovers blood in their urine, they should contact their healthcare provider.
If a test confirms the presence of RBC in the urine, a doctor will likely want to run further tests to figure out what is causing it. Often, the cause is treatable.