What is Blood In Urine?

What is hematuria or bloody urine?

Bloody urine refers to the presence of blood in urine. Hematuria is a medical term that is synonymous with and literally means “Blood in urine”.

Blood in urine can be visible (gross) or invisible (microscopic).

Blood in urine can visible to the eye as pink or red discoloration of urine.  When blood is visible to the eyes, it is called ‘gross hematuria’.

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Blood in urine can also be microscopic where the red blood cells in urine are visible only under the microscope if the urine is examined microscopically. To the eye the urine would look normal yellow. Hematuria when found on urinalysis can be reported as red blood cells in urine or trace of bloody urine.

If you are told that there is a trace of blood in your urine, that can mean a variety of things. That can mean that there is presence of red blood cells in your urine under microscope, that can also mean that a ‘dipstick test’ detects possible presence of blood.

There were 2 tests this report the presence of blood in urine. The dipstick urine test is a chemical test that detects myoglobin and hemoglobin which are chemically similar.  Hemoglobin is present in red blood cells but myoglobin is not.  Therefore the dipstick test sometimes incorrectly reports the presence of bloody urine. Myoglobin can be present after eating meats,  after vigorous exercise, and from eating certain foods. The result of the dipstick test is often reported as trace of blood in urine.  However some laboratories incorrectly try to correlate the presence of red blood cells to the chemical reaction that produces a positive result on a dipstick test. They sometimes report red blood cells per high power field even though microscopic examination of urine was not performed.

It is important to carefully examine the results of urinalysis test to see if it was performed by dipstick or using microscopic evaluation.

Dipstick test is a screening test and if positive for blood requires confirmation with microscopic urinalysis.  The presence of trace of blood in urine on dipstick test suggests that there may be blood in urine and this requires confirmation with microscopic examination of urine to look for red blood cells in urine. Presence of more than 3-5 red blood cells per high power field is concerning.

Microscopic hematuria refers to the presence of more than 3-5 RBCs (red blood cells) per power field on microscopic examination.  This can also be referred to as presence of occult blood in urine, microscopic blood in urine, microscopic hematuria,  RBC (red blood cells) in urine.

Positive dipstick test for blood in urine should NOT be called ‘microscopic hematuria’ unless the test is confirmed using microscopic examination.

In the red blood cells were noted during microscopic examination of urine recall this microscopic hematuria. Depending on patient’s age and various other risk factors microscopic hematuria requires a thorough evaluation.

If you can see the presence of blood in urine with your eyes typically as slightly pink tinged urine or bright red urine or brownish urine we call  that gross hematuria.

Brownish urine can be caused by a variety of problems including presence of blood in urine, very concentrated urine, diet, and nephrological problems such as ATN (acute tubular necrosis).

Gross hematuria requires a thorough urological evaluation regardless of age or sex.

Typically a urologist would be evaluating gross hematuria in men and women as well as and children. However the evaluation can be started by the primary care physician or pediatrician.

 

 

 

Last modified on November 15, 2013