Blood In Urine

The discovery of blood in urine is also referred to as hematuria. It is a potentially warning sign that occurs by many serious diseases. Unlike blood in stool, however, blood in urine finding is often underestimated.


Blood in urine can occur because of bleeding of any part of urinary tract including kidneys, ureters, urinary bladder and urethra. Kidney is a pair abdominal organ. It contains large number of microscopic glomeruli, where blood is filtered into kidney tubules. Filtrated fluid is called primary urine and as it flows through kidney ducts, the majority of its volume is reabsorbed back to bloodstream. The residue (about 1.5 liters per day) flows into hollow space called renal pelvis and then it is lead by ureter into urinary bladder and urethra.


Blood clotting disorders

Blood clotting disorder may be congenital as it is in hemophilia, Von Willebrand's disease and other conditions. Blood clotting problems emerging during person's life are more common and these are usually consequences of anticoagulant medication. If coagulation disorder (followed by bleeding) is caused by drugs, the problems may be theoretically solved by reducing their dose, changing preparations or discontinuing them. The patient should, however, never change doses or discontinue these medications without consulting a doctor.


This is a whole group spectrum of diseases that affect glomeruli in kidneys. In the vast majority of cases these are caused by disorders of immune system that by more possible ways damages glomeruli tissue. Damaged glomeruli allow red blood cells and protein to penetrate into urine. Kidney damage in glomerulonephritis manifests either by blood in urine, or protein in urine, or both. Blood in urine with other symptoms is referred to as nephritic syndrome, excessive protein loss into urine is known as nephrotic syndrome.

Kidney cancer

Blood in urine can be chronic symptom of this insidious cancer. It is one of the reasons why blood in urine shall be further investigated. Let's just add that bleeding can be the only symptom until it is too late for an efficient treatment. As always more information can be found in relevant article dedicated to kidney cancer.

Urinary stones

Urinary stones can injure urinary tracts mucosa and cause bleeding into urine. Blood in urine is, however, not the main patient's complaint. When a stone obstructs urinary tract, colic pain emerges. It is shocking abdominal pain radiating to groin. Pain is often accompanied by vomiting.

Urinary tract infections

Infections are usual causative factors of blood in urine. By infections of lower urinary tract (bladder and below) affected person also complains about burning pain during urination and about frequent urination. Kidney infection (pyelonephritis) usually manifests dramatically with high temperature, painful loin and headache.

Urinary bladder cancer

This cancer, like kidney cancer, can manifest itself for a very long time "only" by occasional findings of blood in urine, and this is another reason why we should never underestimate this symptom. This cause of hematuria is typically not associated with other symptoms.

Prostate cancer

Prostate cancer is another reason why we should not underestimate blood in urine. If there is blood in urine in older men that is accompanied by symptoms of urinary outflow blockage (frequent urination, intermittent flow of urine, feeling of insufficient emptying), it is always suspicious of prostate disorders including prostate tumor presence.

Urinary tract injuries

Injury to any part of the urinary tract during accidents and by urologic surgery and catheterization is usually accompanied by bleeding.

Red urine color non-related to hematuria

Urine can turn red even because of certain medications like some antihelminthic agents used against pinworms.

Gynecological blood

Taking urine sample for urinal exam in menstruating woman or by woman bleeding from gynecological tract may cause urine contamination.


Hematuria can be divided into microhematuria (invisible to naked eye) and macrohematuria (clearly visible). Even small amount of blood causes visible reddish coloration of urine, one milliliter of blood per one liter of urine is enough. Hematuria accompanied by sudden pain is typical for urinary tract infections or urinary stones and painless hematuria is more typical for tumor presence.

Diagnostic approach

When there is suspicion of blood in urine, it is wise to visit a doctor. Medical history should begin the examination. It is important to know about other present symptoms, known medical illnesses and current medication. Urinalysis is the most important of basic examination methods. Urine can be examined by special testing papers dipped in urine, by microscope (centrifuged blood sediment) and by microbiological examination. Using a special test called "phase contrast" allows distinguishing whether red blood cells have penetrated through glomeruli, or whether they have come from lower parts of the urinary tract. Abdominal ultrasound can distinguish various kidney and prostate disorders and also locate dilation of urinary tract by urinary stone obstruction. Endoscopic method can be used to visualize urinary bladder from within (so-called cystoscopy). Further approach is chosen according to outcome of previously named diagnostic methods. When there is suspicion of glomerulonephritides, further diagnostics (including possible kidney biopsy) is performed by nephrologists.


The finding of blood in the urine , either visible to the naked eye , or eye undetectable as an incidental finding during chemical examination of urine from any cause should not be underestimated - especially if it is not accompanied by any other symptoms. There are many very serious diseases (tumors, glomerulonephritis) , which must be diagnosed and treated as soon as possible . Fear of cancer this is not rational, because in the early finding it can often be solved in a relatively easy operations and without any further consequences.

Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources