Blood in the Urine in Cats

4 min read

Hematuria in Cats


Blood in the urine, a condition known as hematuria, may indicate a serious underlying disease process. Familial hematuria (a condition in which blood in the urine runs in certain families of animals) is usually implicated in young cats, while cancer is the usual cause in older cats. Females are at greater risk for urinary tract infections that lead to blood in the urine than are males.




Symptoms of hematuria include blood in the urine, a sign in itself. Red-tinged urine, with or without abnormal frequent passage of urine will be evident. In patients with cancer, a mass may be palpated during physical examination. Abdominal pain will be evident in some patients.


Patients with a blood-clotting disorder may present with subdermal skin hemorrhages, conditions known as petechiae and ecchymoses, which appear as bruises. These discolored spots will be indicated by round, purplish, non-raised patches on the skin.




  • Systemic causes are generally due to coagulopathy (clotting)
  • Low number of platelets or thrombocytes in the blood (a condition known as thrombocytopenia)
  • Diseases of the upper urinary tract are caused by inflammation of the blood vessels (known as vasculitis)
  • Upper urinary tract – the kidneys and ureters:
    • Structural or anatomic disease, such as cystic kidney disease and familial kidney disease
    • Metabolic diseases, such as kidney stones
    • Neoplasia
    • Infectious diseases
    • Nephritis
    • Idiopathic causes
    • Trauma
  • In the lower urinary tract:
    • Infectious disease
    • Inflammatory disease in the kidney
    • Unknown cause
    • Trauma
  • Lower Urinary Tract ‒ bladder and urethra:
    • Structural or anatomic issues such as bladder malformations are implicated in bringing on hematuria
    • Metabolic causes, such as stones, are possible
    • Neoplasia
  • Infectious disease (such as bacterial, fungal, and viral disease):
    • Idiopathic causes
    • Trauma
    • Chemotherapy can elicit hematuria
    • Unknown cause
    • Trauma
  • Issues involving the genitalia include metabolic conditions:
    • Heat cycle, or estrus
    • Neoplasia
    • Cancer or tumors
    • Iinfectious disease such as from bacteria and fungus
    • Inflammatory disease
    • Trauma 



You will need to give a thorough history of your cat's health, including a background history of symptoms, and possible incidents that might have precipitated this condition. The history you provide may give your veterinarian clues as to which organs are causing secondary symptoms. Your veterinarian will perform a thorough physical exam on your cat, with a complete blood profile, including a chemical blood profile, a complete blood count, and a urinalysis. In male cats, examination of an ejaculate sample will help to identify prostatic disease.


Differential diagnoses for blood-tinged urine will include other causes for discolored urine. The common urine reagent strip tests for blood are designed to detect red blood cells, hemoglobin, or protein. Diet will also be considered. If you are supplementing your cat's diet with vitamins or anything different from a regular kibble diet, you will need to share this with your veterinarian, since substantial doses of vitamin C (ascorbic aid) may cause false-negative reagent test strip results.


Ultrasonography, radiography, and contrast radiography may be useful in obtaining a diagnosis. If any mass lesions are indicated, a biopsy may be necessary for a definitive diagnosis. A vaginoscopy in female cats, or a cystoscopy in male cats will rule out neoplasia and lower urinary tract issues.


Related Posts

Urine Testing: Why Test Your Cat's Urine?

Dr. Lorie Huston
Aug 30, 2013

Excess Protein in the Cat's Urine

Cecilia de Cardenas
Feb 28, 2015

Particles in the Urine in Cats

Cecilia de Cardenas
Apr 05, 2015

Glucose in the Urine in Cats

Alex German
May 18, 2011