serum osmolality


Also found in: Dictionary, Thesaurus, Encyclopedia.
Related to serum osmolality: SIADH

osmolality

 [oz″mo-lal´ĭ-te]
the concentration of a solution in terms of osmoles of solutes per kilogram of solvent.
serum osmolality a measure of the number of dissolved particles per unit of water in serum. In a solution, the fewer the particles of solute in proportion to the number of units of water (solvent), the less concentrated the solution. A low serum osmolality means a higher than usual amount of water in relation to the amount of particles dissolved in it, and accompanies overhydration, or edema. An increased serum osmolality indicates deficient fluid volume. Measurement of the serum osmolality gives information about the hydration status within the cells because of the osmotic equilibrium that is constantly being maintained on either side of the cell membrane (homeostasis). Water moves freely back and forth across the membrane in response to the osmolar pressure being exerted by the molecules of solute in the intracellular and extracellular fluids. Serum osmolality reflects the status of hydration of the intracellular as well as the extracellular compartments and thus describes total body hydration. The normal value for serum osmolality is 270–300 mOsm/kg water.
urine osmolality a measure of the number of dissolved particles per unit of water in the urine. A more accurate measure of urine concentration than specific gravity, urine osmolality is useful in diagnosing renal disorders of urinary concentration and dilution and in assessing status of hydration. The normal value is 500 to 800 mOsm/L.

serum osmolality

Etymology: L, serum, whey; Gk, ōsmos, impulse
a measure of the osmotic concentration of blood serum, expressed as the number of osmoles of solute per kilogram of plasma water.

serum osmolality

The osmotic concentration of the serum.
See also: osmolality

osmolality

the concentration of a solution in terms of osmoles of solutes per kilogram of solvent.

serum osmolality
a measure of the number of dissolved particles per unit of water in serum. In a solution, the fewer the particles of solute in proportion to the number of units of water (solvent), the less concentrated the solution. A low serum osmolality would be indicative of a higher than usual amount of water in relation to the amount of particles dissolved in it. It would be expected, then, that a low serum osmolality would accompany overhydration, or edema, and an increased serum osmolality would be present in a state of fluid volume deficit.
Measurement of the serum osmolality gives information about the hydration status within the cells because of the osmotic equilibrium that is constantly being maintained on either side of the cell membrane (homeostasis).
Water moves freely back and forth across the membrane in response to the osmotic pressure being exerted by the molecules of solute in the intracellular and extracellular fluids. Serum osmolality reflects the status of hydration of the intracellular as well as the extracellular compartments and thus describes total body hydration.
urine osmolality
a measure of the number of dissolved particles per unit of water in the urine. A more accurate measure of urine concentration than specific gravity, urine osmolality is useful in diagnosing renal disorders of urinary concentration and dilution and in assessing status of hydration.

serum

pl. sera, serums [L.] the clear portion of any animal or plant fluid that remains after the solid elements have been separated out. The term usually refers to blood serum, the clear, straw-colored, liquid portion of the plasma that does not contain fibrinogen or blood cells, and remains fluid after clotting of blood.
Blood serum from animals whose bodies have built up antibodies is called antiserum or immune serum. Inoculation with such an antiserum provides temporary, or passive, immunity against the disease.

serum albumin mastitis test
a high concentration of serum albumin in milk indicates the presence of mastitis in the quarter.
antilymphocyte serum
serum breaks
in classical swine fever (hog cholera) vaccination when a serum-simultaneous vaccination program is not effective and it is assumed that the hyperimmune serum was ineffective.
serum clot time
see prothrombin consumption test.
serum enzymes
enzymes of individual tissues are released into the blood when the tissue is damaged or when there is much activity in it. The levels are used as a measure of activity or injury.
serum-fast
resistant to the effects of serum.
serum glutamic-oxaloacetic transaminase (SGOT)
serum glutamic-pyruvic transaminase (SGPT)
immune serum
serum from an immunized animal, containing specific antibody or antibodies.
serum osmolality
a measure of the number of dissolved particles per unit of water in serum. See also serum osmolality.
pooled serum
the mixed serum from a number of animals.
serum protein
see serum protein.
serum sickness
a group of immediate or antibody-mediated hypersensitivity reactions (also referred to as type III hypersensitivities) that includes Arthus reaction, serum sickness and immune complex diseases. The pathogenesis involves formation of bulky antibody-antigen complexes in the walls of small blood vessels; the complexes fix complement and cause necrosis and thrombus formation. There is infiltration of polymorphonuclear cells from which lysosomal enzymes are released.
serum-simultaneous immunization
an outdated method of vaccination, most popular at one time in the vaccination of pigs against classical swine fever (hog cholera). Live virus and antiserum to the virus were injected into the patient simultaneously; breakdowns in the system were frequent, leading to severe outbreaks of the target disease.
serum thymic factor
a humoral factor enhancing T lymphocyte responsiveness.
References in periodicals archive ?
Additionally, ingestion of Acacia honey drink could elicit significantly higher values of plasma glucose, plasma insulin and serum osmolality compared to plain water during the rehydration phase and time trial running performance.
Clinical signs of DI include polyuria, dehydration, hypernatremia, and increased serum osmolality.
Adult emergency departments often still give DKA patients an initial bolus of insulin to saturate their receptors, a practice long abandoned in pediatric emergency departments because it can cause serum osmolality to drop too fast, according to Dr.
The goals of therapy with hypertonic saline can be summarized as 1) first, to remove patients with severe manifestations from immediate danger, 2) to correct the patient to a mildly hy-ponatremic level and 3) maintain this level of serum sodium allowing time for the brain to adjust to the change in serum osmolality.
Both patients had hyponatremia, hypochloremia, low serum osmolality, and low urine osmolality caused by voluntary drinking of excessive quantities of water or diluted formula.
3 mg/dL) Blood glucose 135 mg/dL (<100 mg/dL) Urine osmolality 175 mOsm/kg (300 to 1300 mOsm/kg) Serum osmolality 365 mOsm/kg (269 to 298 mOsm/kg) Thyroid-stimulating hormone 0.
ADH is released by the posterior pituitary and controls serum osmolality by causing insertion of water channels in the kidney and hence water reabsorption.
005, serum sodium is greater than 145 mEq/L, and serum osmolality is greater than 295 mOsm/L (Eisenberg & Redick, 1998).
The urine-to-serum osmolality ratio (U/Sosm) was calculated by dividing urine osmolality by serum osmolality.
This disproportionate loss in electrolyte-free water can lead to hypernatremia, resulting in increased serum osmolality and the movement of free water from cells, which can lead to intracellular dehydration.

Full browser ?