urine
(ūr′ĭn)
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[Fr. urine, fr. L. urina, urine]
The fluid and dissolved solutes (including salts and nitrogen-containing waste products) that are eliminated from the body by the kidneys. SEE TABLE: Significance of Changes in Urine SEE TABLE: Common Disorders of Urination
COMPOSITION
Urine consists of approx. 95% water and 5% solids. Solids amount to 30 to 70 g/L and include the following (values are in grams per 24 hr unless otherwise noted): Organic substances: urea (10 to 30), uric acid (0.8 to 1.0), creatine (10 to 40 mg/24 hr in men and 10 to 270 mg/24 hr in women), creatinine (15 to 25 mg/kg of body weight per day), ammonia (0.5 to 1.3). Inorganic substances: chlorides (110 to 250 nmol/L depending on chloride intake), calcium (0.1 to 0.2), magnesium (3 to 5 nmol/24 hr), phosphorus (0.4 to 1.3). Osmolarity: 0.1 to 2.5 mOsm/L.
In addition to the foregoing, many other substances may be present depending on the diet and state of health of the individual. Among component substances indicating pathological states are abnormal amounts of albumin, glucose, ketone bodies, blood, pus, casts, and bacteria.
URINE Red blood cells and one white blood cell (×400)
URINE TESTING KIT Commercial testing kits contain a reagent for a specific substance. A chemical reaction with the urine causes a color change that you interpret using a color chart.
Significance of Changes in Urine
QUANTITY | ||
Normal | Abnormal | Significance |
1000-3000 mL/day | Varies with fluid intake, food consumed, exercise, temperature, kidney function | |
High (polyuria >3000 mL/day) | Diabetes insipidus, diabetes mellitus, water intoxication, chronic nephritis, diuretic use | |
Low (oliguria) | Dehydration, hemorrhage, diarrhea, vomiting, urinary obstruction, or many intrinsic kidney diseases | |
None (anuria) | Same as oliguria | |
COLOR | ||
Normal | Abnormal | Significance |
Yellow to amber | Depends on concentration of urochrome pigment | |
Pale | Dilute urine, diuretic effect | |
Milky | Fat globules, pus, crystals | |
Red | Drugs, blood or muscle pigments | |
Green | Bile pigment (jaundiced patient) | |
Brown-black | Toxins, hemorrhage, drugs, metabolites | |
HEMATURIA (blood in urine) | ||
Normal | Abnormal | Significance |
0-2 RBC/high-powered field (hpf) | Normal (physiological) filtration | |
3 or more RBCs/hpf | Extrarenal: urinary tract infections, cancers, or stones. Renal: infections, trauma, malignancies, glomerulopathies, polycystic kidneys | |
PYURIA (leukocytes in urine) | ||
Normal | Abnormal | Significance |
0-9 leukocytes/hpf | ||
10 or more leukocytes/hpf | Urinary tract infection, urethritis, vaginitis, urethral syndrome, pyelonephritis, and others | |
PROTEINURIA | ||
Normal | Abnormal | Significance |
10-150 mg/day | ||
30-300 mg/day of albumin | Indicative of initial glomerular leakage in diabetes mellitus or hypertension (microalbuminuria) | |
>300 mg/day | Macroalbuminuria. Indicative of progressive kidney failure. Injury to glomeruli or tubulointerstitium of kidney. | |
>3500 mg/day | Nephrotic range proteinuria. Evaluation may include kidney biopsy. | |
SPECIFIC GRAVITY | ||
Normal | Abnormal | Significance |
1.010-1.025 | Varies with hydration | |
1.010 (Low) | Excessive fluid intake, impaired kidney concentrating ability | |
>1.025 (High) | Dehydration, hemorrhage, salt-wasting, diabetes mellitus, and others | |
ACIDITY | ||
Normal | Abnormal | Significance |
Acid (slight) | Diet of acid-forming foods (meats, eggs, prunes, wheat) overbalances the base-forming foods (vegetables and fruits) | |
High acidity | Acidosis, diabetes mellitus, many pathological disorders (fevers, starvation) | |
Alkaline | Vegetarian diet changes urea into ammonium carbonate; infection or ingestion of alkaline compounds |
Common Disorders of Urination
Anuria | Complete (or nearly complete) absence of urination |
Diversion | Drainage of urine through a surgically constructed passage, e.g., a ureterostomy or ileal conduit |
Dysuria | Painful or difficult urination, e.g., in urethritis, urethral stricture, urinary tract infection, prostatic hyperplasia, or bladder atony |
Enuresis | Involuntary discharge of urine, esp. by children at night (bedwetting) |
Incontinence | Loss of control over urination from any cause, e.g., from involuntary relaxation of urinary sphincter muscles or overflow from a full or paralyzed bladder |
Nocturia | Excessive urination at night |
Oliguria | Decreased urinary output (usually less than 500 mL/day), often associated with dehydration, shock, hemorrhage, acute renal failure, or other conditions in which renal perfusion or renal output are impaired |
Polyuria | Increased urinary output (usually more than 3000 mL/day), such as occurs in diabetes mellitus, diabetes insipidus, and diuresis |
URINE (A) white blood cells, (B) squamous epithelial cells, (C) granular cast and uric crystals, (D) fat body (×400)
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Citation
Venes, Donald, editor. "Urine." Taber's Medical Dictionary, 24th ed., F.A. Davis Company, 2021. Nursing Central, nursing.unboundmedicine.com/nursingcentral/view/Tabers-Dictionary/771046/0/urine.
Urine. In: Venes DD, ed. Taber's Medical Dictionary. F.A. Davis Company; 2021. https://nursing.unboundmedicine.com/nursingcentral/view/Tabers-Dictionary/771046/0/urine. Accessed December 2, 2024.
Urine. (2021). In Venes, D. (Ed.), Taber's Medical Dictionary (24th ed.). F.A. Davis Company. https://nursing.unboundmedicine.com/nursingcentral/view/Tabers-Dictionary/771046/0/urine
Urine [Internet]. In: Venes DD, editors. Taber's Medical Dictionary. F.A. Davis Company; 2021. [cited 2024 December 02]. Available from: https://nursing.unboundmedicine.com/nursingcentral/view/Tabers-Dictionary/771046/0/urine.
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