What causes blood in a dog's urine?

Common causes include UTI (most common in females), bladder stones, benign prostatic hyperplasia in intact males, trauma, bladder polyps or cancer, kidney disease, and coagulopathy (clotting disorders). Less commonly: anticoagulant rodenticide poisoning, cyclophosphamide drug toxicity, or idiopathic renal hematuria. The most common serious cause in older dogs is transitional cell carcinoma (bladder cancer).

Is blood in dog urine an emergency?

Go to the ER immediately if: your dog cannot urinate at all, is straining repeatedly with no output, has large blood clots in urine, is visibly in pain or collapsed, or you know or suspect rat bait (anticoagulant rodenticide) ingestion. A small amount of blood in otherwise normal-appearing urine with no straining can usually wait for a same-day or next-day vet appointment.

What does the color of blood in dog urine mean?

Pink or light red urine: small amount of blood, often early infection or mild inflammation. Bright red urine or visible clots: significant active bleeding — bladder stones, trauma, severe infection, or tumor. Dark red or brown urine: older blood (kidney source or concentrated blood) OR hemoglobinuria from red blood cell destruction (not true blood in urine). Brown urine that clears with standing suggests hemoglobin or myoglobin rather than intact red blood cells.

What does blood in dog urine with no other symptoms mean?

Blood without straining, urgency, or pain can be UTI (common), bladder polyp, early bladder stone, prostate issue (intact males), or occasionally early bladder cancer. It should always be evaluated — bladder cancer (transitional cell carcinoma) in dogs often presents as recurrent blood in urine without dramatic symptoms, especially in Scottish Terriers, Shetland Sheepdogs, West Highland White Terriers, and Beagles.

Can a UTI cause blood in dog urine?

Yes. UTI is the most common cause of blood in a female dog's urine. Bacteria inflame the bladder wall, causing bleeding alongside frequent urination, accidents, and straining. A urine culture confirms the infection and identifies the right antibiotic. Blood usually resolves within days of treatment. Recurrent UTI with blood warrants ultrasound to look for bladder stones or anatomical abnormalities.

Do bladder stones cause blood in dog urine?

Yes. Bladder stones (uroliths) are a very common cause of blood and straining in dogs. The stones physically abrade the bladder wall. Common stone types: struvite (often infection-associated, can dissolve with diet) and calcium oxalate (require surgical removal or laser lithotripsy). X-ray and ultrasound can detect most stone types.

Can prostate problems cause blood in dog urine?

Yes — in intact male dogs, prostate disease is a major cause of blood in or around urine. Benign prostatic hyperplasia (BPH) affects over 80% of intact males over 5 years. Prostatitis (prostatic infection) causes fever, pain, and blood. Both can cause dripping of blood-tinged fluid from the prepuce independent of urination. Neutering resolves BPH completely.

What is transitional cell carcinoma in dogs?

Transitional cell carcinoma (TCC), also called urothelial carcinoma, is the most common bladder cancer in dogs. It typically grows at the bladder trigone (base), causing persistent blood in urine, straining, and recurrent UTI-like symptoms. It occurs most often in older female dogs. High-risk breeds: Scottish Terriers (18x higher risk), Shetland Sheepdogs, Beagles, West Highland White Terriers. Diagnosed by urine cytology, ultrasound, or BRAF mutation test (Cadet BRAF assay).

What is the difference between blood and hemoglobin in dog urine?

The dipstick tests positive for both. True hematuria has intact red blood cells visible on urine sediment exam. Hemoglobinuria (from immune-mediated hemolytic anemia or other red blood cell destruction) has a positive dipstick but no or very few intact RBCs on sediment. Brown/red urine that is clear rather than turbid often suggests hemoglobin or myoglobin rather than intact blood. A sediment exam distinguishes them.

What tests does a vet run for blood in dog urine?

Standard workup includes: urinalysis with sediment (confirm true hematuria and look for bacteria, casts, crystals), urine culture, abdominal X-ray (for radio-opaque stones), abdominal ultrasound (bladder wall, kidneys, prostate, masses). For recurrent or refractory cases: urine cytology for cancer cells, BRAF mutation test (Cadet BRAF) for TCC, coagulation panel if clotting disorder suspected, CBC and chemistry panel.

Blood in Dog's Urine: Causes, Colors & When It's an Emergency

Go to the ER immediately if your dog cannot urinate at all or strains repeatedly with no output, has large blood clots in urine, is visibly in pain or has a distended abdomen, is collapsed or very weak, or may have eaten rat bait (anticoagulant rodenticide).

Blood found on your dog's urinalysis?

Upload the full urinalysis to see RBC count, sediment findings, and context alongside USG, protein, and culture results.

Check My Dog's Urinalysis

Finding blood in your dog's urine — whether you see it yourself or it shows up on a routine urinalysis — is understandably alarming. Most causes are treatable, but a few require urgent attention. Knowing what the color, timing, and accompanying signs point to will help you act quickly and ask the right questions at the vet.

What Urine Color Tells You

Light pink

Mild

Meaning: Small amount of blood. Common with early UTI or mild bladder inflammation.

Action: Same-day or next-day vet visit; urine culture

Bright red

Significant

Meaning: Active bleeding. Bladder stones, trauma, prostate disease, or mass.

Action: Vet within hours; X-ray and ultrasound needed

Red with clots

Urgent

Meaning: Heavy hemorrhage. Stones, tumor, trauma, or coagulopathy.

Action: Emergency vet — same day

Dark red / brown

Investigate

Meaning: Older blood (kidney source) OR hemoglobin/myoglobin (not true blood). Brown urine that is clear rather than turbid suggests hemoglobin.

Action: Urgent vet; sediment exam to distinguish

Blood only at start

Urethral/Prostate

Meaning: Urethra or prostate bleeding — intact male dogs most commonly.

Action: Vet exam; prostatic assessment

Blood only at end

Bladder neck

Meaning: Bladder neck or trigone — where TCC most often grows.

Action: Ultrasound; urine cytology

Appearance	Suggests	Typical Cause	Action
Light pink	Mild	Early UTI, mild inflammation	Same-day vet; urine culture
Bright red	Significant	Bladder stones, trauma, prostate, tumor	Vet within hours; X-ray + ultrasound
Red with clots	Urgent	Heavy hemorrhage — stones, tumor, coagulopathy	Emergency vet
Dark red / brown	Investigate	Old blood from kidney OR hemoglobinuria	Urgent; sediment exam to distinguish
Blood at stream start	Urethra/Prostate	Prostatic disease (intact males), urethral issue	Vet exam; prostatic assessment
Blood at stream end	Bladder neck	Bladder neck / trigone — TCC location	Ultrasound; urine cytology

True Blood vs Hemoglobin vs Myoglobin

All three turn the dipstick positive for blood — but they mean very different things:

• True hematuria — intact red blood cells in urine; looks cloudy-red or pink. Sediment shows >5 RBCs per HPF. Causes: UTI, stones, tumor, trauma, kidney disease.
• Hemoglobinuria — free hemoglobin from destroyed RBCs; urine is red but clear (not cloudy), with few or no intact RBCs on sediment. Plasma is also pink-red. Cause: hemolytic anemia (IMHA). See anemia in dogs.
• Myoglobinuria — muscle protein from severe muscle damage; urine is brown-red and clear, plasma is normal color. High CK confirms rhabdomyolysis. Causes: heat stroke, severe seizures, exertion.

Understand Your Dog's Full Urinalysis

Upload the complete urinalysis to see RBCs, WBCs, bacteria, casts, and crystals together — the full picture makes the cause clearer.

Analyze My Dog's Results

Most Common Causes by Sex and Age

• UTI (female dogs, any age) — by far the most common cause in females; their short, wide urethra makes ascending bacterial infection easy. Symptoms: frequent small urinations, accidents indoors, licking at vulva. Urine culture identifies the organism. See UTI in dogs.
• Prostatic disease (intact males) — over 80% of intact males over 5 have benign prostatic hyperplasia (BPH), which causes blood-tinged discharge from the prepuce, often dripping between urinations. Prostatitis causes fever, pain, and systemic illness. Neutering resolves BPH completely.
• Bladder stones — uroliths abrade the bladder wall, causing recurrent blood and straining. Struvite stones can dissolve with prescription diet + antibiotics; calcium oxalate stones (more common in males, Miniature Schnauzers, Bichons, Shih Tzus) require surgery or laser lithotripsy. X-ray detects most stone types; ultrasound catches radiolucent ones. See bladder stones in dogs.
• Transitional cell carcinoma (TCC) — the most common bladder cancer in dogs, growing at the trigone (bladder base). Classic pattern: dog briefly responds to antibiotics then blood returns — often mistaken for recurrent UTI for months. Scottish Terriers (18× higher risk), Shetland Sheepdogs, West Highland White Terriers, Beagles, and Wire Fox Terriers are highest-risk. Diagnosed by ultrasound, urine cytology, or the Cadet BRAF assay (detects BRAF V595E mutation in ~85% of canine TCC).
• Kidney sources — blood from kidneys or ureters appears uniformly throughout the entire stream. Causes: kidney stones, pyelonephritis (also causes fever and abnormal kidney values), glomerulonephritis, renal tumor, trauma, idiopathic renal hematuria.
• Coagulopathy / anticoagulant rodenticide poisoning — hematuria alongside bruising, nosebleeds, coughing blood, or bloody stool suggests a clotting disorder. Rat baits (brodifacoum, bromadiolone) deplete vitamin K–dependent clotting factors 3–5 days after ingestion. Coagulation panel confirms; treatment is vitamin K1 for 4–6 weeks. Von Willebrand disease (common in Dobermans) can cause recurrent hematuria with no other symptoms.
• Cyclophosphamide-induced hemorrhagic cystitis — dogs on cyclophosphamide chemotherapy can develop severe bladder inflammation from the toxic metabolite acrolein. Prevented with hydration and MESNA; requires stopping cyclophosphamide if it occurs.

What Your Vet Will Do

Urinalysis with sediment — confirms true hematuria (intact RBCs), identifies WBCs (infection), bacteria, casts (kidney damage), and crystals (stone type)

Urine culture — identifies bacteria and guides antibiotic choice; essential even when bacteria aren't visible on sediment

Abdominal X-ray — detects radio-opaque stones (struvite, calcium oxalate) and prostatic enlargement

Abdominal ultrasound — evaluates bladder wall thickness, masses, stones (including radiolucent ones X-ray misses), kidneys, and prostate

Urine cytology or Cadet BRAF test — for recurrent blood in older dogs or high-risk breeds where TCC is suspected

CBC and chemistry panel — kidney values, platelet count, and coagulation panel if systemic disease or clotting disorder is suspected

Key Takeaway

Blood in urine always warrants a vet visit — even if your dog seems otherwise fine. UTI and bladder stones are the most common causes and are very treatable. But recurrent blood that partially responds to antibiotics is the classic warning sign for bladder cancer in older dogs, especially Scottish Terriers and Shelties.

Never assume a second course of antibiotics will fix recurrent hematuria without imaging. The earlier TCC is diagnosed, the more management options are available.

Want a Vet's Take on This?

Get a vet's interpretation of your dog's urinalysis and symptoms — no appointment needed.

Talk to a Vet Online — Today →

30% off with code PETS30

We may earn a commission if you purchase through this link, at no extra cost to you.

Track Your Dog's Urinary Health

Upload your dog's urinalysis to VetLens and instantly see:

✓ RBC count and what the sediment findings mean
✓ Whether infection, crystals, or casts are also present
✓ How findings fit with kidney values and blood pressure
✓ What to ask your vet about next steps

Check My Dog's Urinalysis

Frequently Asked Questions

My dog had blood in urine once and it stopped — should I still go to the vet?

Yes. A single episode of visible blood should still be evaluated with a urinalysis and urine culture. Blood that stops on its own can mean the cause is intermittent (stones, early tumor). The Cadet BRAF test for bladder cancer can be run on a urine sample without a vet visit in some circumstances.

Can stress cause blood in a dog's urine?

Stress-induced hematuria is well established in cats (see FLUTD) but much less common in dogs. In dogs, blood should be assumed to have a physical cause until proven otherwise. Rule out UTI, stones, and prostatic disease before attributing it to stress.

How do I tell if my dog is straining to urinate or defecate?

Watch the posture: straining to urinate involves squatting or lifting a leg repeatedly with little or no urine output. Straining to defecate involves a squatting posture with visible effort producing stool, or no stool. Male dogs can be harder to assess — watch for dribbling, licking, or repositioning multiple times in a short span.

Does blood in urine mean my dog has cancer?

No — UTI and bladder stones are far more common than cancer. But persistent blood that recurs after antibiotic treatment, especially in a dog over 8 and particularly in high-risk breeds (Scottish Terrier, Sheltie, Westie, Beagle), needs imaging and possibly the Cadet BRAF test to rule out TCC before repeating another antibiotic course.

Can diet cause blood in a dog's urine?

Indirectly. Diets very high in certain minerals can promote crystal and stone formation. Struvite stones are associated with certain diets and infections; calcium oxalate stones with low-moisture, high-protein diets and genetic predisposition. Feeding a balanced diet with adequate water (wet food or added water) reduces stone risk.

Blood in a Dog's Urine: Causes, Colors & When It's an Emergency