Hematuria (Blood in the Urine) in Cats

Hematuria at a glance

  • About: Blood in the urine (hematuria) may be seen in the urine or picked up during a urine test. Hematuria may be due to a urinary tract disorder or a platelet disorder.
  • Symptoms: May not be apparent, or you may notice a red colour in the urine. Other symptoms will vary depending on the underlying cause.
  • Diagnosis: Baseline tests, diagnostic imaging, and blood clotting tests.
  • Treatment: Address the underlying cause.


Hematuria is the presence of red blood cells in the urine and is a symptom of an underlying disorder. As there are many causes of hematuria in cats which range from mild to life-threatening, prompt veterinary attention is required for any cat who develops blood in the urine.

Types of hematuria

Hematuria can be microscopic or gross.

  • Microscopic hematuria: The urine appears normal, but upon microscopic examination, red blood cells are found to be present.
  • Gross hematuria: The cat’s urine is visibly discoloured due to the high numbers of red blood cells.

Hematuria causes

The most common causes of hematuria are cystitis (inflammation or infection of the bladder and feline lower urinary tract disease, which consists of a group of conditions that affect the cat’s lower urinary tract system and bladder). Other causes include:


  • Trauma such as a car accident or a heavy fall
  • Blood clotting disorders such as hemophilia or thrombocytopenia
  • Polycythemia (increased red blood cells)
  • Certain medications
  • Idiopathic (no known cause)

Upper urinary tract (kidneys and ureters):

Lower urinary tract (bladder and urethras):

Additional symptoms

Symptoms of hematuria can vary depending on the underlying cause. Blood in the urine may be evident if there is a large quantity, with the urine taking on a red or pink hue. Other common symptoms which relate to urinary tract disorders can include the following:

  • Frequent passage of small amounts of urine
  • Straining to urinate
  • Urinating outside the litter tray
  • Crying in the litter tray
  • Urinating outside the litter tray
  • Genital licking which goes beyond regular grooming
  • Abdominal pain
  • Fever
  • Lethargy
  • Bleeding from the gums or nose
  • Depression
  • Anorexia (loss of appetite)


Your veterinarian will perform a physical examination of your cat and obtain a history including accompanying symptoms you may have noticed. Blood that is present only at the beginning of urination may suggest bleeding from the lower urinary tract, bleeding which is present at the end of urination may point to bleeding from the upper urinary tract and bleeding that is present throughout the urine is likely to originate from the kidneys, ureters or bladder. These can all help your veterinarian narrow down the cause of hematuria.

Diagnostic workup:

  • Urinalysis: The presence of white blood cells may indicate urinary tract infection. Protein in the urine may indicate kidney disease.
  • Complete blood count: To check for anemia, white blood cells, red blood cell casts, and cancer cells.
  • Biochemical profile: Evaluate kidney and liver function as well as electrolytes.
  • Abdominal ultrasound: To look for stones, tumours, and kidney size.
  • Intravenous pyelogram (IVP): This is a contrast x-ray examination of the kidneys, ureters, and bladder. A contrast material is injected into the patient and collects in the kidneys and urinary tract, which, allows the veterinarian to assess the kidneys and urinary tract.
  • Blood clotting tests: Prothrombin time and activated partial thromboplastin time.
  • Cystoscopy: A tube-like instrument (cystoscope) is used to evaluate the bladder and urethra.


Urinary tract infection:

Antibiotics to kill the bacteria and increasing water consumption such as switching to a wet diet and introducing a water fountain. Keep litter trays clean at all time.


A completely blocked cat is a medical emergency will need to have urine removed via a needle inserted directly into the bladder or catheterisation and fluids to correct electrolyte imbalances.

Home care includes a stone dissolving prescription diet and increasing water consumption to dilute the urine and prevent the formation of crystals.

Stones that can’t be dissolved will need surgical removal.

Bladder and kidney stones:

Prescription diet to dissolve the stones. Urinary acidifiers to change the urine pH and if the stones cannot be dissolved, surgical removal will be necessary.


Surgery to remove cancer, and chemotherapy and/or radiotherapy as a follow up where indicated.

Blood clotting disorders:

Treatment depends on the underlying cause but may include injection of vitamin K, corticosteroids to slow down platelet destruction and blood transfusion where necessary.

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  • Julia Wilson, 'Cat World' Founder

    Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio

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