Visible (gross) hematuria is urine that is visibly discolored by blood or blood clot. It may present as urine that is red to brown, or as frank blood. As little as 1 mL of blood can impart color to 1 L of urine.
Visible hematuria, even when transient or asymptomatic, may indicate a significant disease process and always requires further investigation. Possible etiologies vary by age and the workup of visible hematuria differs among children and adults, depending on their risk factors.
Patients with visible hematuria represent a higher-risk group for urologic malignancy than those presenting with nonvisible hematuria.[1] [2] Pooled incidence rates of 17%, 2%, and 0.75% for urothelial bladder cancer, renal cell carcinoma, and upper tract urothelial carcinoma, respectively, have been reported among patients undergoing investigation for visible hematuria.[2] Visible hematuria prevalence may be more than 68% in patients with urologic cancer.[3]
The sensitivity of visible hematuria in revealing malignancy is significant: 0.83 for urothelial carcinoma of the bladder, 0.66 for ureteric carcinoma, and 0.48 in renal cell carcinomas.[4] In men ages >60 years, the positive predictive value of visible hematuria for urologic malignancy is 22.1%, and in women of the same age it is 8.3%.[5]
- Male sex
- Increasing age
- Smoking
- Exposures to benzene, aromatic amines, carcinogens, chemotherapy, or high doses of analgesics
- A history of:
- irritative voiding symptoms
- chronic urinary tract infection
- indwelling urinary catheter
- pelvic irradiation.
