Hematuria — presence of blood in the urine

Types and characteristics

Clinically, hematuria is described as either gross (visible) or microscopic. Gross hematuria is when the urine is discolored and blood is apparent to the eye. Microscopic hematuria is detected on urinalysis or microscopy when red blood cells are present but the urine looks normal. The pattern, associated symptoms and laboratory features help localize the source within the urinary tract or kidneys.

Common causes

• Infections of the urinary tract or bladder, which often cause burning or frequency.
• Kidney or ureteral stones that irritate the lining and produce bleeding.
• Benign prostatic enlargement or other prostate conditions in men.
• Glomerular diseases originating in the kidney, sometimes producing protein in urine or other signs of kidney dysfunction.
• Trauma, recent procedures, or vigorous exercise.
• Malignancy of the urinary tract (bladder, kidney, ureter) — a possible but less common cause, especially in older adults or smokers.

When to investigate

Any unexplained hematuria usually prompts further evaluation. A clinician often starts with a repeat urinalysis and urine microscopy, urine culture to exclude infection, and assessment of kidney function. Imaging studies or direct visualization of the bladder (cystoscopy) may be recommended when initial tests do not explain the bleeding or when risk factors for serious disease are present.

Evaluation overview

Evaluation balances likelihood of benign causes against the need to exclude serious disease. Simple steps include confirming the presence of blood and ruling out contamination (for example, menstrual blood). More detailed assessment may include urine cytology, ultrasound or CT imaging, and specialist referral. Patients and clinicians communicate symptoms, past medical history, and exposures to guide testing.

Treatment and outlook

Treatment depends on the underlying cause. Infections are treated with antibiotics; stones may be managed conservatively or with procedures; glomerular disease requires specialist care; tumors are managed according to oncologic principles. Many causes resolve without long-term consequences, but unexplained or persistent hematuria warrants timely follow-up to exclude serious conditions.

For general information on blood in the urine see blood in urine, and for guidance about when hematuria might indicate a more serious condition consult resources on serious urinary disease at serious causes.