Visual hematuria: urine containing red blood that is visible to the patient. Microscopic or test paper hematuria: The presence of blood confirmed by microscopic examination of the urine or by test paper testing, both in association with other urological symptoms (“symptomatic microscopic hematuria”) and possibly during routine medical examinations, such as for insurance purposes (“asymptomatic microscopic hematuria “). There are many definitions of microscopic hematuria, such as greater than or equal to 3 red blood cells (RBCs) per high-powered view, or greater than or equal to 5, or greater than or equal to 10. Urine test strips detect hemoglobin, i.e., they detect the presence of hemoglobin and myoglobin in the urine. Hemoglobin catalyzes the oxidation of o-toluidine by organo-peroxidase, producing a blue complex. The test paper is able to detect the amount of hemoglobin released by 1 or 2 red blood cells on the right. False positive urine test strips: Occurs in the presence of myoglobin, bacterial peroxidase, povidone, and hypochlorite. False-positive urine test paper (rare): occurs in the presence of reducing agents, such as vitamin C blocking the oxidation of chemical o-toluidine. Is microscopic hematuria or test paper hematuria abnormal? A small amount of red blood cells can be present in the urine of a normal person. The upper limit of normal erythrocyte excretion is 1 million per 24 hours (derived from healthy medical students), and of normal male soldiers who have had their urine tested annually for 12 consecutive years, 40% have had at least one episode of microscopic hematuria, and 15% have had two or more. Temporary microscopic hematuria may occur after strenuous exercise, after sexual intercourse, or from menstrual contamination. The fact that the presence of red blood cells in the urine is normal explains why a certain percentage of patients with microscopic or test paper hematuria, or even sarcoid hematuria, can present normally (i.e., no abnormal findings) on a hematology test. In about 50% of subjects with carnaroscopic hematuria and 70% with microscopic hematuria, there were no abnormal findings despite a complete routine urological examination, including urine cytology, cystoscopy, renal ultrasonography, and intravenous urography (IVU). Urological causes of hematuria 1. cancer: bladder (TCC, SCC), kidney (adenocarcinoma), renal pelvis and ureter (TCC), prostate; 2. stones: kidney, ureter, bladder; 3. infection: bacterial, mycobacterial (TB), parasitic (schistosomiasis), infectious urethritis; 4. inflammation: cyclophosphamide cystitis, interstitial cystitis; 5. trauma: kidney, bladder, urethra (e.g., catheterization injury), pelvic fracture causing urethral rupture; 6, renal cystic disease: e.g., medullary sponge-like kidney; 7, other urologic causes: BPH (hypertrophic blood-rich), lumbago-hematuria syndrome, vascular malformations; 8, hematuria caused by nephrotic causes predisposed to occur in young adults and children, usually including IgA nephropathy, post-infectious glomerulonephritis; less commonly, also membranous proliferative Other “medical” causes of hematuria include congenital coagulation disorders (e.g., hemophilia), anticoagulant therapy (e.g., warfarin), sickle cell disease, renal papillary necrosis, vascular diseases (e.g., renal thrombosis causing infarction and hematuria); 10. Nephrotic causes are more commonly seen in the following conditions: children and young adults, proteinuria, and red blood cell tubularity. Common urological tests for hematuria include urine culture, urine cytology, cystoscopy, renal ultrasonography, and intravenous urography when urinary tract infection with “cystitis” is suspected as the basis. Diagnostic cystoscopy Today, this test is usually performed with a fiberoptic cystoscope, unless radiography confirms bladder cancer, in which case cystoscopy can be abandoned in favor of immediate rigid cystoscopy under anesthesia with biopsy and transurethral resection of bladder tumor – TURBT. Should cystoscopy be performed in patients with asymptomatic microscopic hematuria? The American Urological Association (AUA) Best Practice Strategy for asymptomatic microscopic hematuria recommends cystoscopy in all patients at high risk for microscopic hematuria (patients at high risk for developing TCC, see below for risk factors). In asymptomatic, low-risk patients younger than 40 years of age, the strategy states that “cystoscopy may be appropriately delayed,” but if so, cytology of the urine should be performed. However, the AUA also states that “in low-risk patients with persistent hematuria, the decision to perform cystoscopy should be made by the individual patient after careful discussion between the patient and physician. Our principle is to inform such patients that the likelihood of detecting bladder cancer is low, but even so, we recommend a flexible cystoscopy. Patients then decide whether to undergo cystoscopy based on their perception of “low risk”. If no cause of hematuria (microscopic or visual) is found, is further testing needed? Some think so, citing studies showing that in a small number of patients, additional tests such as retrograde ureterography, ureteral and pelvic endoscopy (ureteroscopy), enhanced CT, and renal angiography can confirm the presence of a range of diseases. Others believe it is not necessary, citing evidence that patients who originally had microscopic hematuria or carnal hematuria (although no further testing was performed) were not found to have developed significant urologic cancer during their 2- to 4-year follow-up. When performing urine cytology, cystoscopy, renal ultrasonography and intravenous urography are normal, we may perform CT scan of kidney and ureter and retrograde ureterography in the following cases 1. Patients with high risk factors for TCC; 2. Microscopic or test paper hematuria persisting for 3 months; 3. Persistent meatus hematuria.