What is hematuria?
Hematuria is the term for red blood cells (RBC’s) in the urine commonly referred to as blood in the urine. This is not a normal phenomenon and the presence of red blood cells raises the concern about some kidney or urinary tract disease leading to bleeding.
Hematuria will not always result in a visible reddish discoloration of the urine. Often it is so subtle that a person may not be aware of any problem until the urine is tested (dipstick, laboratory urinalysis). It is also important to bear in mind that a red discoloration of the urine may not always be due to hematuria. Certain foods, drinks and supplements can cause a reddish discoloration of the urine.
Types of Hematuria
There are different terms that are used to describe hematuria.
Visibly discolored urine appearing red or bloody. Sometimes the urine may also appear dark, ranging from a orange-brown to yellow-brown in color. Black urine on the other hand is the presence of free heme (UK ~ haem) in the urine after red blood cells have been destroyed in the blood. While a cloudy urine is a sign of hematuria, it may also indicate the presence of pus in the urine.
This indicates red blood cells in the urine that is not visible to the naked eye. Upon microscopic examination, more than 5 red blood cells in urine sediment per high-power field in 3 is evident thereby confirming hematuria.
This term is used to describe red blood cells in the urine without other urine abnormalities like protein in the urine (proteinuria) or urinary casts (kidney diseases).
The term benign indicates a condition that is not progressing and should not cause any serious complications. Benign hematuria may mean that it is a transient condition and may resolve spontaneously and is a term often used concurrently with essential hematuria.
Benign familial hematuria refers to a genetic type of kidney disease that begins in childhood and results in hematuria because of abnormalities in the kidney’s filtration apparatus known as the glomerulus.
Essential hematuria means blood in the urine due to no known cause. This term may also be used with benign hematuria – benign essential hematuria – to indicate blood in the urine due to unknown causes, that is not progressing or leading to any complications and may resolve spontaneously.
This is not a term on its own but rather refers to the presence of red blood cells in the urine with no other symptoms like frequent urination, painful urination, urging or incontinence which would normally accompany a pathological urinary disturbance.
Bloody Color of Urine
Gross hematuria does not always mean that the urine will appear red in color. It can appear pink to orange or yellow-brown. Rarely, black urine may also be a sign of hematuria due to free heme in the urine. A number of foods and drugs may cause hematuria or urine discoloration. It is often painless in these instances.
- Rhubarb (red or orange-brown)
- Levodopa (more brown-black)
- Laxative containing senna (more orange-brown)
- Certain antipsychotic drugs