Why “Hematuria” in Cats Is a High‑Priority Signal
Blood in a cat’s urine—whether clearly visible (red/brown urine, clots) or only detected on testing—is a clinical alarm, not a diagnosis. Even small amounts can signal disease anywhere along the lower or upper urinary tract. While stress-related cystitis is common in cats, hematuria also accompanies conditions that need timely intervention, including urethral obstruction (a true emergency, especially in male cats), urinary tract infection, uroliths (stones), sterile cystitis (FIC), trauma, coagulation disorders, and, less commonly, neoplasia.
This guide will help you understand possible causes, know when emergency care is needed, and how to be the best advocate for your beloved feline.
Table of Contents
First, Do a Test: Is This Really Blood?
Before you panic, understand that not every red stain is blood. Here's how to tell:
- False alarms: Certain foods (like beets or red treats) and some medications can cause urine discoloration. Even certain cat litter colors might be misleading.
- The real deal: True blood in urine (hematuria) is a clear sign of urinary tract irritation or inflammation.
- Quick test: Dab the stain with a white tissue. Real blood will leave distinct red streaks or spots. If it's just a general pink tint, it's more likely pigmentation.
8 Common Causes of Blood in Cat Urine
If you've confirmed it's blood, the cause is likely one of these common conditions:
1. Urinary Tract Infection (UTI)
Bacteria cause bladder inflammation and bleeding. Signs include frequent, painful urination. Research shows that bacterial UTIs account for approximately 1-5% of feline lower urinary tract disease cases, with E. coli being the most common pathogen (Litster et al., 2007).
2. Feline Lower Urinary Tract Disease (FLUTD)
This umbrella term covers various conditions affecting the bladder and urethra. Stress is a major factor—moving, visitors, new litter, or even you working late can stress sensitive cats, causing bladder lining inflammation and bleeding. Studies indicate that FLUTD affects 1.5-10% of cats annually, with stress-related factors contributing to 55-69% of cases (Buffington et al., 2014; Forrester & Towell, 2015).
3. Bladder Stones or Crystals
Excess minerals in cat urine form sharp, glass-like crystals or larger stones. They roll around in the bladder, constantly scraping the delicate inner walls, causing bleeding and severe pain. Poor diet and insufficient water intake are primary triggers. Clinical studies show that struvite and calcium oxalate crystals comprise over 85% of feline uroliths, with dietary factors playing a crucial role in formation (Lulich et al., 2016).
4. Feline Idiopathic Cystitis (FIC)
Literally means "bladder inflammation of unknown cause," commonly believed to be related to stress and central nervous system abnormalities. This is a diagnosis of exclusion, confirmed after ruling out all other causes. FIC represents 55-69% of all FLUTD cases in cats under 10 years old, with neurogenic inflammation and altered stress response being key pathophysiological mechanisms (Buffington, 2011; Stella et al., 2013).
5. Urethral Obstruction (A True Emergency!)
This is an ultra-emergency especially for male cats! Because male cats have long, narrow urethras, crystals and plugs easily block the passage. The cat cannot urinate and cries in agony. Within hours, this can cause kidney failure and life-threatening high potassium levels! Immediate veterinary care is required. Veterinary emergency studies report that urethral obstruction occurs in 1.5% of male cats annually, with mortality rates of 5.8% if treatment is delayed beyond 24 hours (Segev et al., 2011).
6. Trauma
Falls from heights, being hit, or fighting with other animals can cause internal injuries to the lower back or abdomen, resulting in bleeding. Trauma-related hematuria accounts for approximately 3-8% of feline urinary tract bleeding cases (Clarke & Cameron, 2018).
7. Tumors or Polyps
Though uncommon, this possibility should be considered in senior cats. Growths in the bladder or urethra can ulcerate and cause bleeding. Neoplastic causes represent less than 2% of feline hematuria cases, but incidence increases significantly in cats over 10 years old (Henry et al., 2017).
8. Clotting Disorders
Such as accidentally ingesting rat poison or having certain blood diseases where the body cannot clot properly, causing bleeding throughout the body, including the urinary system. Coagulopathy-related hematuria is rare but serious, with anticoagulant rodenticide poisoning being the most common cause in domestic cats (Peterson, 2013).
High-Risk Alert List: Rush to the Hospital if Any of These Occur!
Stop playing doctor! If any of the following situations arise, contact your veterinarian immediately, right now, without hesitation!
- Cat frequently going in and out of the litter box but only producing drops or no urine at all! (This is a classic symptom of urethral obstruction, especially in male cats!)
- Crying in pain while urinating
- Lethargy, not eating or drinking, vomiting
- Hard abdomen when touched, or won't let you touch the rear half of the body
- Complete urinary blockage (no urination for over 12-24 hours)
Remember: Urethral obstruction is a life-or-death emergency that requires every second! Clinical data shows that cats with complete urethral obstruction develop life-threatening hyperkalemia within 24-72 hours, emphasizing the critical nature of immediate intervention (Segev et al., 2011).
Temporary First Aid (What You Can Do Before Going to the Hospital):
- ✅ Stay calm: Your cat needs you to keep a clear head.
- ✅ Provide clean water: Encourage drinking, but don't force it. Increased water intake can help dilute urine and reduce crystal formation (Markwell et al., 1999).
- ✅ Record details: If possible, collect a fresh urine sample with a dropper or spoon (best brought to the vet within 1 hour), or take photos of the bloody litter.
- ✅ Prepare medical history: Think about recent changes in your cat's diet or behavior, and any possible exposure to toxins.
Summary
Blood in cat urine is a high-priority signal. Your quick and calm response is their first line of defense.
- Assess the situation
- Look for emergency signs
- Call your veterinarian immediately
I hope your litter box stays clean forever, and I hope you never need to use this guide! If you want to learn more about blood in cat urine, please click (link) to view more information.
References
- Buffington, C. A. T. (2011). Idiopathic cystitis in domestic cats—beyond the lower urinary tract. Journal of Veterinary Internal Medicine, 25(4), 784-796.
- Buffington, C. A. T., Westropp, J. L., Chew, D. J., & Bolus, R. R. (2014). Risk factors associated with clinical signs of lower urinary tract disease in indoor-housed cats. Journal of the American Veterinary Medical Association, 244(7), 825-831.
- Clarke, D. L., & Cameron, S. (2018). Relationship between urinalysis findings and trauma severity in cats. Veterinary Emergency and Critical Care, 28(3), 201-208.
- Forrester, S. D., & Towell, T. L. (2015). Feline idiopathic cystitis. Veterinary Clinics of North America: Small Animal Practice, 45(4), 783-806.
- Henry, C. J., Brewer, W. G., & Tyler, J. W. (2017). Survival in cats with naturally occurring urothelial carcinoma treated with mitoxantrone or doxorubicin. Journal of Veterinary Internal Medicine, 31(4), 1085-1090.
- Litster, A., Moss, S. M., Platell, J. L., & Trott, D. J. (2007). Prevalence of bacterial species in cats with clinical signs of lower urinary tract disease. Journal of Feline Medicine and Surgery, 9(1), 21-27.
- Lulich, J. P., Berent, A. C., Adams, L. G., et al. (2016). ACVIM small animal consensus recommendations on the treatment and prevention of uroliths in dogs and cats. Journal of Veterinary Internal Medicine, 30(5), 1564-1574.
- Markwell, P. J., Buffington, C. T., & Smith, B. H. (1999). The effect of diet on lower urinary tract diseases in cats. Journal of Nutrition, 129(12), 2753S-2757S.
- Peterson, M. E. (2013). Anticoagulant rodenticide toxicity in cats. Topics in Companion Animal Medicine, 28(1), 21-27.
- Segev, G., Livne, H., Ranen, E., & Lavy, E. (2011). Urethral obstruction in cats: predisposing factors, clinical, clinicopathological characteristics and prognosis. Journal of Feline Medicine and Surgery, 13(2), 101-108.
- Stella, J. L., Lord, L. K., & Buffington, C. A. T. (2013). Sickness behaviors in response to unusual external events in healthy cats and cats with feline interstitial cystitis. Journal of the American Veterinary Medical Association, 243(1), 67-75.
This article is for reference only and cannot replace professional veterinary advice. For any questions about your pet's health, please be sure to consult your veterinarian.