Please note: This information was current at the time of publication but now may be out of date. This handout provides a general overview and may not apply to everyone. 

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Am Fam Physician. 2005;71(1):135-136

What is microscopic hematuria?

“Microscopic” means something is so small that it can be seen only through a microscope. “Hematuria” (say “he-mah-tur-ee-ah) means blood in the urine.

So if you have microscopic hematuria, you have red blood cells in your urine, but you cannot see the blood when you urinate.

What causes microscopic hematuria?

Here are some common causes of blood in the urine:

  • Urinary tract (bladder) infection

  • Swelling in the filtering system of the kidneys

  • A stone in your bladder or in a kidney

  • Some diseases that run in families, like cystic kidney disease

  • Some medicines

  • A blood disease, like sickle cell anemia

  • A tumor in your urinary tract (this may or may not be cancer)

  • Vigorous exercise (this usually will go away in 24 hours)

How will my doctor check for microscopic hematuria?

Your doctor usually will want you to give a urine sample. He or she will test your urine for red blood cells. Your doctor also will check for other things that might explain what is wrong. For example, white blood cells in your urine usually mean that you have an infection. If you have blood in your urine, your doctor will ask you some questions to find out what caused it.

If the cause is not clear, you may have to have more tests. You might have an ultrasound test or a test called an intravenous pyelogram (this is like an x-ray). Special tools might be used to look inside your bladder. These tests usually are done by a urologist (a doctor with special training in kidney problems).

How do I give a urine sample?

A nurse will give you an antiseptic wipe (to clean yourself) and a sterile urine collection cup. Write your name on the cup if the nurse does not do this for you. In the bathroom, wash your hands with soap and warm water first.

• For women: Use the antiseptic wipe to clean outside your vagina by wiping yourself from front to back three times before you urinate into the cup. Fold the wipe each time you use it, so that you are wiping with a clean part each time.

• For men: Use the antiseptic wipe to clean the head of your penis. If you are not circumcised, pull the foreskin back behind the head of the penis before you use the wipe. Move the wipe around the head of your penis before you urinate into the cup.

• Start urinating in the toilet. About halfway through the urination, start catching the urine in the cup.

• Wash your hands with soap and warm water.

• Give the sample to the nurse. Someone will look at your urine under a microscope to see if it has blood in it.

What will my doctor do if I have microscopic hematuria?

If the cause of the blood in your urine is found, your doctor will probably treat you. Then your doctor will check your urine again to see if the blood is gone. If the cause is not found, your doctor may do more tests or refer you to a urologist.

Remember that it is always important to find out the cause of blood in your urine.

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