Blood In the Urine: Here Is What You Need To Know

Should you be concerned about hematuria?

By OpenStax College [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons

WHAT DOES THE TERM "HEMATURIA" MEAN

The word hematuria implies the presence of blood in the urine.  The amount of blood may or may not be significant enough for it to be visible to the naked eye.  Hence one could have hematuria without being aware of it. When urine tests indicate the presence of blood in the urine, but it's not visible to the naked eye, it is specifically called microscopic hematuria.

 

IS HEMATURIA AN ABNORMAL FINDING? SHOULD YOU BE WORRIED?

Typically normal healthy urine is not supposed to have blood cells in it.  The way the kidneys' filter is set up, red blood cells are too large to pass through it and usually will not get through into the urine. However, hematuria is a physical finding.  Its diagnosis by itself tells one nothing about why it's there. 

Hematuria therefore may or may not represent a pathological state.  There are instances where people with a normal urinary tract can have hematuria as well.  This causes are discussed later.  It is also important to remember that the amount of blood in the urine may or may not correlate with the severity of the underlying illness.  Gross hematuria (or hematuria that is clearly visible to the naked eye) may sometimes happen after infections and should not be concerning for long-term sequelae. Microscopic hematuria on the other hand, in spite of its name, could be associated with concerning illnesses.

HOW IS HEMATURIA DIAGNOSED

Most people will be told about the presence of hematuria after being incidentally discovered on routine urine tests.  If you have microscopic hematuria, the only way to make a diagnosis would be by collecting a urine sample and doing a test called a urine analysis.  It is a simple test where the technician will place a strip of paper called a dipstick in the urine.

 The dipstick is designed to change color based on the presence of certain abnormal substances in the urine.  Blood is one of those substances.  If the dipstick changes color to indicate the presence of blood, you might receive a diagnosis of hematuria

Remember however that the dipstick test can sometimes be false positive.  In other words it can interpret substances that are not really blood, as blood.  Therefore other things can fool the dipstick and give you a false-positive diagnosis of hematuria.  When this is suspected, the diagnosis needs to be confirmed by a microscopic exam of the urine.  If no red cells are seen on a microscopy exam, you might have received a false-positive diagnosis of hematuria.  

Substances that can create this situation are the presence of myoglobin in the urine (which is the pigment found in the muscles and is often released in periods of muscle breakdown, or from medications like cholesterol lowering medications or statins), or even free hemoglobin (which is often seen in the urine when red cells in the blood break down for various reasons).

WHAT SYMPTOMS MIGHT YOU HAVE IF YOU HAVE HEMATURIA

Most people with microscopic hematuria would not even know that they have it.  Hence there might not be any symptoms. However gross hematuria will obviously be reported by patients, and this is usually seen as the presence of red, pink, or brown urine.  

You could still have other symptoms related to the underlying cause  for hematuria.  For instance people with kidney stones could report flank pain.  If urinary tract infection is causing the hematuria, fever or burning when you pee may be reported.

WHAT ARE COMMON CAUSES OF BLOOD IN THE URINE

Abnormalities of the urinary tract located all the way from the kidneys down to the tip of the urethra could cause blood to appear in the urine and therefore be the reason behind hematuria. The reasons could range from benign non-concerning causes like vigorous exercise, to concerning ones like cancer. A list would include (this is not a complete list):

The affected person may or may not be able to differentiate between all these possibilities. Diagnostic workup might require extensive testing including imaging of the urinary tract and if you have persistent hematuria, it might be a good idea to have yourself evaluated by a nephrologist or a urologist. 

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