While microscopic blood in your urine may not be a medical emergency, visible blood in your urine is associated with a number of serious health issues, including kidney disease and urologic cancer.

Between 2% and 30% of adults will have blood in their urine at some point. But most of the time, this blood can only be seen under a microscope. Blood in your urine that’s visible to your naked eye is known as gross hematuria, or macrohematuria.

Although there’s a wide variety of things that can cause hematuria, macrohematuria that’s visible to your naked eye is always a cause for deeper investigation.

This article will review some of the common causes and health conditions associated with macrohematuria.

Hematuria is the name for any presence of blood in your urine. In most cases of hematuria, there are only a handful of red blood cells in a urine sample. These cells can’t be seen by your naked eye. They’re found only through examination under a microscope, hence the name microhematuria.

There are also some rapid dip-stick type urine tests that can alert you to the presence of any blood cells in your urine.

Macrohematuria, on the other hand, is visible when you urinate. Just 1 milliliter of blood in 1 liter of urine can create discoloration that’s noticeable to your naked eye.

What to do if you see blood in your urine

If there’s enough blood in your urine to create discoloration or visible strings and clots, get medical attention right away. Visible blood in your urine is associated with a number of serious health problems.

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Hematuria has many causes, but macrohematuria that’s visible in the form of discolored urine or stringy blood clots tends to appear with more serious conditions.

Some of the most common conditions or situations associated with hematuria in general include:

These situations usually don’t require intensive treatment or ongoing health problems. But the things that cause macrohematuria that produce visible blood or clots are usually more serious.

Below are some conditions that are often associated with macrohematuria or blood clots in your urine.


Visible blood in your urine is the first symptom that gets noticed in about 66% of people who turn out to have some form of urologic cancer. Cancers that can fall into this category include:

Beyond blood in your urine, signs and symptoms you might develop with these types of cancer include:

Blood clotting disorders

Disorders that affect your body’s ability to clot blood can also cause hematuria. Blood that can’t clot effectively becomes too thin and may pass to areas where it isn’t normally found. Hemophilia is one disorder like this.

Hemophilia is an inherited blood clotting disorder. It’s caused by a genetic mutation that’s passed through families that prevents blood from clotting effectively. People with this disorder may have blood in their urine or stool, as well as other signs and symptoms that indicate a bleeding problem like:

  • spontaneous bleeding
  • bleeding into your joints
  • bloody gums
  • frequent and difficult to control nosebleeds
  • easily bruised skin

Blood thinning medications (anticoagulants)

People may also develop bleeding in their urine from blood thinning medications — also called anticoagulants — such as warfarin (Jantoven).

Other anticoagulants include:

Sickle cell trait

Sickle cell trait is another disorder that can lead to micro- or macrohematuria. People with sickle cell trait inherit one mutated gene from a parent with sickle cell trait and one normal gene from the other parent.

Sickle cell disease only develops when you inherit two sickle cell genes, one from each parent. People who carry a sickle cell gene but don’t have sickle cell disease have sickle cell trait.

You likely won’t notice any symptoms of sickle cell disease if you only have sickle cell trait, but you can still pass the gene on to your children. If the other parent also carries sickle cell trait and passes a sickle cell gene on to your child, they could develop sickle cell disease.

Even without development of sickle cell disease, people with sickle cell trait may have symptoms and complications from the single sickle gene, including:

  • visible or microscopic blood in their urine
  • an increased risk of kidney diseases
  • pain
  • muscle loss

These signs and symptoms usually appear under specific conditions in people with sickle cell trait, such as:

Kidney disease

Beyond cancers, bleeding and blood cell diseases, or obvious injuries that could cause blood in your urine, there are a number of kidney diseases that can produce this symptom.

  • Glomerulonephritis: Glomerulonephritis is one of these diseases. It develops when the parts of your kidneys that filter bodily fluids become inflamed, damaged, or irritated. Other symptoms of glomerulonephritis besides blood in your urine include things like puffiness in your face, decreased urination, and shortness of breath.
  • Interstitial nephritis: Interstitial nephritis is kidney damage that’s usually the result of taking certain drugs or medications or having another disorder that leads to acute kidney injury. Beyond blood in your urine, signs and symptoms can include things like fever, rash, and a change in your levels of a particular type of immune cell (eosinophilia).
  • Polycystic kidney disease: Polycystic kidney disease develops when small, fluid-filled cysts form in your kidneys. Over time, these cysts can reshape and enlarge your kidneys, leading to signs and symptoms like high blood pressure, chronic kidney disease, and kidney failure.

If blood or blood clots are visible, a doctor or healthcare professional will want you to provide a urine sample for analysis. Even without obvious blood in your urine, a urine sample will help a doctor identify the presence of even a few blood cells (microscopic hematuria).

If your urine sample contains blood, a doctor will typically order additional tests and procedures to try and identify the cause. These can include:

What will my doctor want to know?

To understand why there’s blood in your urine, a doctor will ask questions about your individual and family health history, recent injuries or illnesses, and any other symptoms you may be having.

It’s helpful if you can tell the doctor when you first noticed discoloration or clots in your urine, as well as any other symptoms or problems that were occurring around that same time. It’s also helpful if you can describe the size, shape, and color of any blood clots you’ve seen in your urine.

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If you can see blood clots in your urine, or your urine turns brown or red, make an appointment to see a doctor as soon as possible.

There are many things that can cause blood cells to show up in your urine, and not all of them are serious. But blood clots or blood that you can see in your urine is almost always a symptom of a serious condition that requires an immediate diagnosis and treatment.