Urine
osmolality is a measure of
urine
Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (mal ...
concentration,
in which large values indicate concentrated urine and small values indicate diluted urine. Consumption of water (including water contained in food) affects the osmolality of urine.
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Overview
Osmolality is measured by osmometer, which evaluates the freezing point depression of a solution and supplies results as milliosmoles per kilogram of water while specific gravity is measured by colorimetric strips, refractometer,
hydrometer
A hydrometer or lactometer is an instrument used for measuring density or relative density of liquids based on the concept of buoyancy. They are typically Calibration, calibrated and Graduation (instrument), graduated with one or more scales suc ...
and pyknometer.
In healthy humans with restricted fluid intake, urine osmolality should be greater than 800
mOsm/kg, while a 24-hour urine osmolality should average between 500 and 800 mOsm/kg.
Urine osmolality in humans can range from approximately 50 to 1200 mOsm/kg, depending on whether the person has recently drunk a large quantity of water (the lower number) or has gone without water for a long time (the higher number).
Plasma osmolality with typical fluid intake often averages approximately 290 mOsm/kg H
2O in humans.
In other animals
Some mammals are capable of higher osmolality than humans. This includes rats (approximately 3,000 mOsm/kg H
2O), hamsters and mice (approximately 4,000 mOsm/kg H
2O), and chinchillas (approximately 7,600 mOsm/kg H
2O)
See also
*
Plasma osmolality
References
External links
Synthetic Urine
Human physiology
Urine
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