What Does Invisible Blood in Urine Mean?

Allow me to paint you a picture. Perhaps you have been urinating more frequently than often or are feeling a burning sensation as you pee. But you do not seem to see anything that is wrong and your pee looks normal. So you decide to take an Icle test to see if there is any blood in your pee. And unfortunately, the test pad turns green or blue, which indicates that you do have blood in your pee. But it is invisible to the naked eye. Let us be honest, discovering you have blood in your urine can be a terrifying thought.

Having invisible blood in the urine is known as microscopic hematuria. It simply means you have red blood cells in your urine and since they are so small, they cannot be viewed unless under a microscope. So what exactly does invisible blood in your urine mean?

Well, it can go either way. In some cases, invisible urine may be no cause of alarm. However, in other cases, it could be an indication of a serious condition. Here are a couple of reasons why you may have invisible blood in your urine.

Urinary Tract Infection (UTI)

A urinary tract infection occurs when bacteria from your bowels or the external environment travels up your urethra causing an infection in your urinary tract. While anyone can get a UTI, women are usually more prone to it than men. This is usually because a woman’s urethra is closer to her anus, where bacteria are usually common.

UTIs usually cause symptoms such as a burning sensation while you urinate, frequent urination, or foul-smelling urine. However, in older adults, the symptom that may indicate they have a UTI is invisible blood in their urine.

Bladder or Kidney Stones

In some cases, when urine has an excessive amount of minerals such as calcium, oxalate, and uric acid. These minerals may crystalize and form deposits in your bladder or kidney. These then go on to become the famously painful to remove kidney and bladder stones, that we all know and hate. Now while these stones are inside your urinary tract, they are generally painless. However, some of these stones may scratch the walls of your urinary tract. The blood from these scratches will then mix in with your urine, ultimately causing you to have invisible or even visible blood in your urine.

Enlarged Prostate

An enlarged prostate, which is also known as benign prostatic hyperplasia, is a condition that mainly affects men over the age of 50. The prostate is regarded as a walnut-shaped gland that is an essential part of the male reproductive system. However, as men grow older this particular may begin to swell due to the imbalance of testosterone and estrogen in the body. This is because as men grow older, the amounts of testosterone in their bodies begin to reduce, leading the prostrate to enlarge. This enlargement causes symptoms such as difficulty starting urination, dribbling at the end of urination, or a weak flow during urination.

Plus invisible blood in the urine can also be an indication of an enlarged prostate. Since an enlarged prostate can press on the urethra it can irritate it. Thus leading to microscopic blood in your urine.


Glomerulonephritis is a type of kidney disease characterized by the damage of glomeruli. Glomeruli are filtering units found in our kidneys and are made up of a unit of capillaries. They help the kidneys filter blood to remove waste and extra fluid. When the glomeruli get damaged, usually by becoming inflamed or scarred, glomerulonephritis occurs. This messes with the kidney filtering system causing traces of blood and protein to pass into your urine. It is for this reason why finding microscopic blood in your urine is a common symptom of glomerulonephritis. Other symptoms include high blood pressure, urination more often or lesser than usual, or puffiness in the face or legs.

Polycystic Kidney Disease

This is an inherited kidney disease that results in your kidneys growing numerous fluid-filled cysts in your body. If these cysts grow too big or become too many, they can cause crowd out the tissue in your kidney and cause permanent damage to your kidneys. Microscopic blood in your urine can be an indicator that you have polycystic kidney disease.


Cancers can be a dangerous condition. However early detection of cancers can be lifesaving for most cancers. Invisible blood in your urine can be an early symptom of cancers involving the urinary tract such as prostate, kidney, or bladder cancer. According to a study at the University of Exeter Medical School, it found that 1 in 60 people over the age of 60 who had invisible blood in their urine turned out to have blood cancer.

For kidney cancers, while blood in urine is not usually that common, really large tumors in the kidney can cause invisible blood in the urine.


Sometimes invisible blood in your urine may not be an indication of something wrong with your body. It can be due to the medication you are taking. Some medications such as penicillin, aspirin, and cyclophosphamide, a drug used to treat certain types of cancer can cause invisible blood in the urine. Blood thinners such as heparin and warfarin can also lead to red blood cells appearing in your urine.

Tough Physical Workout

Though not common, strenuous exercise can cause microscopic blood to appear in your urine. While the main cause of this is usually unknown, it has been caused by something as simple as dehydration or trauma to the kidneys or bladder that can occur during a difficult physical exercise routine. It can also be due to the breakdown of red blood cells that occurs with prolonged cardio.

These are just some of the things that having invisible blood in your urine could mean. While in some cases having microscopic blood in your urine may be harmless, in some cases it can be an indication of a serious condition. We always recommend that when you find invisible blood in your urine, even if you think it is harmless, you should always consult a doctor.