urine

urine is a topic covered in the Taber's Medical Dictionary.

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(ūr′ĭn)

[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.

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URINE Red blood cells and one white blood cell (×400)
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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
NormalAbnormalSignificance
1000-3000 mL/dayVaries 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
NormalAbnormalSignificance
Yellow to amberDepends on concentration of urochrome pigment
PaleDilute urine, diuretic effect
MilkyFat globules, pus, crystals
RedDrugs, blood or muscle pigments
GreenBile pigment (jaundiced patient)
Brown-blackToxins, hemorrhage, drugs, metabolites
HEMATURIA (blood in urine)
NormalAbnormalSignificance
0-2 RBC/high-powered field (hpf)Normal (physiological) filtration
3 or more RBCs/hpfExtrarenal: urinary tract infections, cancers, or stones. Renal: infections, trauma, malignancies, glomerulopathies, polycystic kidneys
PYURIA (leukocytes in urine)
NormalAbnormalSignificance
0-9 leukocytes/hpf
10 or more leukocytes/hpfUrinary tract infection, urethritis, vaginitis, urethral syndrome, pyelonephritis, and others
PROTEINURIA
NormalAbnormalSignificance
10-150 mg/day
30-300 mg/day of albuminIndicative of initial glomerular leakage in diabetes mellitus or hypertension (microalbuminuria)
>300 mg/dayMacroalbuminuria. Indicative of progressive kidney failure. Injury to glomeruli or tubulointerstitium of kidney.
>3500 mg/dayNephrotic range proteinuria. Evaluation may include kidney biopsy.
SPECIFIC GRAVITY
NormalAbnormalSignificance
1.010-1.025Varies with hydration
1.010 (Low)Excessive fluid intake, impaired kidney concentrating ability
>1.025 (High)Dehydration, hemorrhage, salt-wasting, diabetes mellitus, and others
ACIDITY
NormalAbnormalSignificance
Acid (slight)Diet of acid-forming foods (meats, eggs, prunes, wheat) overbalances the base-forming foods (vegetables and fruits)
High acidityAcidosis, diabetes mellitus, many pathological disorders (fevers, starvation)
AlkalineVegetarian diet changes urea into ammonium carbonate; infection or ingestion of alkaline compounds

Common Disorders of Urination
AnuriaComplete (or nearly complete) absence of urination
DiversionDrainage of urine through a surgically constructed passage, e.g., a ureterostomy or ileal conduit
DysuriaPainful or difficult urination, e.g., in urethritis, urethral stricture, urinary tract infection, prostatic hyperplasia, or bladder atony
EnuresisInvoluntary discharge of urine, esp. by children at night (bedwetting)
IncontinenceLoss of control over urination from any cause, e.g., from involuntary relaxation of urinary sphincter muscles or overflow from a full or paralyzed bladder
NocturiaExcessive urination at night
OliguriaDecreased 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
PolyuriaIncreased urinary output (usually more than 3000 mL/day), such as occurs in diabetes mellitus, diabetes insipidus, and diuresis

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URINE (A) white blood cells, (B) squamous epithelial cells, (C) granular cast and uric crystals, (D) fat body (×400)

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