Blood in the urine — what it means and what happens next.

Visible vs. microscopic hematuria

Visible (gross) hematuria means urine that is noticeably pink, red, brown, or cola-colored. Even a small amount of blood — less than a teaspoon in a typical bladder full of urine — is enough to make urine visibly discolored. Any visible blood needs prompt evaluation.

Microscopic hematuria is blood detected only by a lab test — either on a dipstick or under a microscope. The standard definition is at least 3 red blood cells per high-power field on a microscopic exam. This is commonly found incidentally on a routine urine test.

Common causes

In approximate order of frequency in adults:

• Urinary tract infection — irritation of the bladder lining bleeds easily.
• Kidney stones — sharp edges abrade the urinary tract.
• BPH / enlarged prostate — enlarged prostate tissue is fragile and bleeds.
• Vigorous exercise — particularly running. Usually resolves within 48 hours.
• Recent procedures — catheterization, cystoscopy, biopsy.
• Medications — blood thinners, NSAIDs in high doses.
• Menstrual contamination (in women).
• Prostate cancer, bladder cancer, or kidney cancer — less common but what we want to rule out.
• Kidney diseases — glomerulonephritis and others. Often evaluated alongside a nephrologist.

Standard workup

For anyone with visible hematuria (or significant microscopic hematuria with risk factors), the standard urologic workup has three parts:

1. Urine tests

• Urinalysis and microscopy to confirm blood cells.
• Urine culture to rule out infection.
• Urine cytology — examining cells shed in urine under a microscope to look for cancer cells. Less sensitive than newer tests but widely available.

2. Imaging of the upper urinary tract

CT urogram is the preferred study. This is a CT scan with contrast, timed in three phases to show the kidneys, ureters, and bladder sequentially. It identifies stones, masses, and structural abnormalities.

For patients who can't get a CT (kidney function, contrast allergy), alternatives include renal ultrasound and MRI urogram.

3. Evaluation of the bladder — cystoscopy

A cystoscopy (see our cystoscopy guide) looks directly at the inside of the urethra and bladder. Most bladder cancers are visible on cystoscopy. This is the single most important test for ruling out bladder cancer.

What the results usually show

For most patients, the workup finds:

• No abnormality (idiopathic hematuria) — very common. We typically monitor with periodic urine tests but otherwise leave alone.
• BPH or a stone — treat the underlying issue.
• A small lesion requiring biopsy — done at the same or a follow-up procedure.

Who has the highest risk of finding cancer

• Men over 35
• Smokers and former smokers
• People with occupational exposure to certain chemicals (dyes, rubber, leather, paint)
• History of pelvic radiation
• History of cyclophosphamide chemotherapy
• Previous bladder cancer
• Persistent symptoms (urgency, frequency) alongside hematuria

Patients in these categories deserve a thorough, expedited workup. Even microscopic hematuria in a 60-year-old male smoker carries enough risk to justify the full evaluation.

After the workup

Depending on findings:

• Normal workup — we usually recheck urine in 6 months. If still present, a repeat workup may be indicated at 3–5 years.
• Identified cause — treat the cause and recheck.
• Suspicious finding — proceed with biopsy or targeted treatment as indicated.