Blood in Urine: Causes & When to Worry (Hematuria Guide)

What is hematuria? (Gross vs microscopic)

Hematuria is the medical term for blood in urine. It comes in two forms:

• Gross hematuria: You can see blood with the naked eye – urine may look pink, red, cola‑colored, or have visible clots. This is always abnormal and requires evaluation.
• Microscopic hematuria: Blood is only visible under a microscope. It is often found incidentally on a routine urinalysis. Even without visible blood, it can signal underlying disease.

At Vivekananda Hospital, we evaluate all patients with hematuria – even a single episode – because the cause can range from harmless (e.g., vigorous exercise) to serious (e.g., kidney cancer).

Common causes of blood in urine (kidney stones, infection, etc.)

Most causes of hematuria are not life‑threatening, but they still need diagnosis. Common causes include:

• Kidney stones: The most common cause of gross hematuria with pain. Stones irritate the ureter or renal pelvis, causing bleeding. Blood may be visible only during pain episodes.
• Urinary tract infection (UTI): Infection of the bladder (cystitis) or kidney (pyelonephritis) causes inflammation and bleeding. Usually accompanied by burning, frequency, and fever.
• Enlarged prostate (BPH): In men, an enlarged prostate can cause blood in urine due to engorged veins on the prostate surface.
• Strenuous exercise: “Jogger’s hematuria” – temporary bleeding from bladder wall trauma or breakdown of red blood cells. Resolves with rest.
• Medications: Blood thinners (aspirin, warfarin, clopidogrel) can cause hematuria even without underlying disease.
• Menstruation: In women, vaginal blood can contaminate the urine sample – a repeat clean‑catch specimen is needed.

Serious causes: cancer, glomerulonephritis, trauma

Although less common, hematuria can be a sign of serious conditions that require prompt treatment:

• Bladder cancer: The most common cause of painless gross hematuria in older adults (over 50). Smoking is a major risk factor.
• Kidney cancer (renal cell carcinoma): Can cause microscopic or gross hematuria, often without pain. May also cause flank mass or weight loss.
• Glomerulonephritis: Inflammation of the kidney’s filtering units – causes cola‑colored urine, high blood pressure, and swelling.
• Kidney injury (trauma): From accidents, falls, or contact sports – often with severe pain.
• Polycystic kidney disease: Inherited condition with multiple cysts – hematuria from cyst bleeding.

Kidney stones and hematuria – what to expect

If you have a kidney stone, hematuria is extremely common – up to 90% of patients have either visible or microscopic blood. Here is what to expect:

• Timing: Blood often appears when the stone moves and irritates the ureter. It may come and go with pain episodes.
• Appearance: Usually pink or light red. Dark brown or cola‑colored suggests older blood or glomerular bleeding.
• Clots: Small stringy clots are possible. Large clots or heavy bleeding (like tomato juice) is not typical for a simple stone – may indicate a bleeding disorder or tumour.
• Does blood mean the stone is passing? Not necessarily. Blood indicates irritation, not movement. Even a stone stuck in the ureter can cause persistent hematuria.

If you have a known stone and see blood, it is usually not an emergency unless you have fever, severe pain, or heavy clots. However, if this is your first episode of hematuria without a known stone, you need imaging.

When to worry – red flags and emergency signs

See a doctor promptly (within days) if you have any hematuria. Go to the emergency department immediately if you have:

• Heavy bleeding with large clots – especially if you cannot urinate.
• Fever with hematuria – possible kidney infection.
• Severe flank or abdominal pain that prevents you from standing still.
• Inability to urinate despite feeling the urge.
• Known solitary kidney or kidney failure.
• Hematuria after a recent fall or accident (possible kidney injury).

Even without emergency signs, you should see a urologist within 2 weeks for any unexplained gross hematuria. Microscopic hematuria can be evaluated on a non‑urgent basis.

How is hematuria evaluated? (Tests and workup)

At Vivekananda Hospital, we follow a systematic approach for hematuria evaluation:

• Urinalysis and microscopy: Confirms blood and looks for red blood cell shape (dysmorphic RBCs suggest glomerular disease), white blood cells (infection), and crystals (stones).
• Urine culture: To rule out infection.
• Blood tests: Creatinine (kidney function), CBC (anemia, platelets), coagulation profile (if on blood thinners).
• Imaging: Non‑contrast CT scan (CT KUB) to look for stones, masses, or structural abnormalities. For suspected cancer, CT urography with contrast.
• Cystoscopy: A thin camera passed into the bladder to visualise the lining. This is the gold standard for ruling out bladder cancer. It takes 2‑3 minutes in clinic.
• Kidney ultrasound: For patients who cannot have CT (pregnancy, young adults) – less sensitive but safe.

If you are over 35, smoke, or have risk factors for bladder cancer, cystoscopy is mandatory for gross hematuria.

Interactive FAQ – Blood in urine

Disclaimer: Blood in urine always deserves medical attention. Do not assume it is from a stone without imaging. If you have hematuria, consult a urologist at Vivekananda Hospital for proper evaluation.