Human health and medicine

Uridine triacetate

Uridine triacetate (triacetyluridine, PN401), brands Vistogard and Xuriden, is an oral prodrug of uridine; FDA-approved 2015 for hereditary orotic aciduria and as an emergency antidote for fluorouracil or capecitabine overdose and toxicity.

Urinalysis

Urinalysis is a laboratory test examining the physical, chemical, and microscopic properties of urine to detect kidney disease, urinary tract infection, liver disease, and metabolic disorders such as diabetes.

Urinary Antibody-Coated Bacteria Test

Urinary antibody-coated bacteria (ACB) test, a 1974 fluorescent antibody technique detecting antibody-coated bacteria in urine sediment to localize urinary tract infection to kidney versus bladder; sensitivity about 83%, specificity about 77%, now rarely used.

Urinary cast

Urinary casts (casts in the urine) are tube-shaped particles formed from Tamm-Horsfall protein in kidney tubules, seen on urinalysis microscopy. Hyaline casts are normal; RBC casts indicate glomerulonephritis, granular casts acute tubular necrosis.

Urinary catheterization

Urinary catheterization: draining the bladder via indwelling Foley, intermittent, suprapubic, or condom catheters. Covers 3,500-year history, CAUTI risk (75% of hospital UTIs), and CDC prevention guidance.

Oct 20, 2026

Urinary Catheters

Urinary catheters: tubes inserted into the bladder or kidney (urethral, suprapubic, ureteral, Foley) to drain urine. Key facts: 75% of hospital UTIs are catheter-associated; prolonged use is the main CAUTI risk factor.

Urinary diversion

Urinary diversion is surgery that reroutes urine from the kidneys or bladder to an external stoma or internal reservoir when the urinary tract is absent or damaged.

Urinary incontinence

Urinary incontinence, also called bladder leakage, is the unintentional passing of urine. Types include stress, urge, overflow, total, and mixed; first-line treatment is pelvic floor muscle training, bladder training, and lifestyle change.

Urinary kallidinogenase

Urinary kallidinogenase (HUK, 尤瑞克林) is a 238-amino-acid tissue kallikrein extracted from human urine, approved in China in 2005 for mild-to-moderate acute thrombotic ischemic stroke; it dilates ischemic-region microvessels via the kallikrein-kinin system, with blood-pressure reduction as its main adverse effect.

Urinary meatus

Urinary meatus (external urethral orifice): the opening of the urethra to the outside, at the tip of the penis in males and just anterior to the vaginal opening in females; site of hypospadias and meatal stenosis.

Urinary retention

Urinary retention: inability to empty the bladder, acute (sudden, emergency catheterization) or chronic (incomplete emptying, PVR over 50 mL). Causes include outlet obstruction, detrusor underactivity, and dyssynergia; treated with catheters, drugs, or surgery.

Urinary Sediment Analysis

Urinary sediment analysis, also called urine sediment microscopy, is the microscopic and chemical examination of urine sediment for cells, casts, crystals, and bacteria; a MeSH-indexed part of urinalysis used to diagnose kidney and urinary tract disease.

Urinary system

Urinary system (urinary tract, renal system): the kidneys, ureters, bladder, and urethra, which filter blood, produce 1-2 quarts of urine daily, store it, and void it; kidneys also regulate blood pressure, erythropoiesis, and vitamin D.

Urinary tract infection

Urinary tract infection (UTI): bacterial infection of the bladder (cystitis), urethra, or kidney (pyelonephritis), usually by E. coli entering the urethra; far more common in women, treated with antibiotics, about 8 million US doctor visits yearly.

Urinary tract infection following delivery

Urinary tract infection following delivery (ICD-11 JB40.3, puerperal cystitis or pyelonephritis) is postpartum bacterial UTI. Risk rises with cesarean delivery, catheterization, tocolysis, renal disease, and preeclampsia; only about 25% of cases show typical dysuria.

Urinary tract infection, site not specified

Urinary tract infection, site not specified (ICD-10-CM N39.0; ICD-11 GC08) is the billing and classification code for a UTI whose anatomical site is undocumented, with organism-specific subcodes, exclusion rules, and clinical context on diagnosis and antibiotic treatment.

Urinary tract reconstruction

Urinary tract reconstruction is surgery to repair, replace, or reroute the urinary tract, most often after cystectomy, using an ileal conduit, continent pouch, or neobladder.

Urination

Urination (micturition, voiding): expulsion of urine from the bladder through the urethra, controlled by pontine and spinal reflexes, parasympathetic pelvic nerves, sympathetic storage pathways, and voluntary cortical control.

Urine

Urine: liquid waste made by the kidneys filtering blood, about 1-2 L/day, pH 4.5-8.0. Also called pee. Basis of urinalysis, pregnancy and drug tests; once thought sterile, now known to host a urobiome.

Urine culture

Urine culture is a laboratory test that grows and counts microbes from a urine sample to identify the organism causing a urinary tract infection and its antibiotic susceptibilities.

Urine cytology

Urine cytology is a diagnostic pathology method that microscopically examines cells shed into urine to detect urothelial carcinoma; it is highly specific but only moderately sensitive, best for high-grade tumors.

Urine specimen collection

Urine specimen collection is the clinical procedure of obtaining a urine sample by midstream clean catch, catheterization, or suprapubic aspiration for urinalysis, culture, and other testing.

Urine test strip

Urine test strip (dipstick, reagent strip): plastic strip with dry-chemistry pads detecting glucose, protein, blood, ketones, nitrite, leukocyte esterase, pH, and more; from Maumené 1850 and Oliver 1883 to Clinistix 1956.

Urine therapy

Urine therapy, also called urotherapy, urinotherapy, or shivambu, is the practice of drinking or applying urine as a remedy. Ancient practice from India onward, but no clinical evidence of benefit and documented risks.

Urocanic aciduria

Urocanic aciduria (urocanase deficiency, encephalopathy due to urocanase deficiency, OMIM 276880) is an extremely rare autosomal recessive histidine metabolism disorder caused by UROC1 deficiency, causing urinary urocanic acid with variable ataxia and intellectual deficit, often benign.

Urodynamic testing

Urodynamic testing is the study of urine storage and evacuation by the lower urinary tract, recording bladder pressures to diagnose the cause of urinary symptoms.

Urodynamics

Urodynamics (UDS): tests measuring bladder pressure and urine flow (uroflowmetry, cystometry, pressure-flow studies) to diagnose bladder outlet obstruction and detrusor underactivity; UPSTREAM trial found no routine benefit.

Urofacial syndrome

Urofacial syndrome (Ochoa syndrome, UFS) is a rare autosomal recessive disorder of bladder voiding dysfunction with inverted facial expression on smiling, caused by biallelic HPSE2 (~64%) or LRIG2 (~20%) variants, risking renal failure.

Uroflowmetry

Uroflowmetry is a noninvasive diagnostic test that measures the flow rate of the urinary stream in mL/s, used as first-line screening for lower urinary tract symptoms.