serum osmolality


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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 ?
In support of this observation, there was a relatively lower serum osmolality as the volume of fluid ingested increased in this study.
The specific research questions of this study were (a) whether significant alterations in serum osmolality, [[Na.
Diagnosis of cerebral salt-wasting syndrome (CSWS) and syndrome of inappropriate antidiuretic hormone secretion (SIADH) (1,23) PARAMETER CSWS SIADH Serum Na (mmol/L) <135 <135 Serum osmolality (mosm/kg) <285 <285 Urine osmolality (mosm/kg) >200 >200 Urine Na (mmol/L) >25 >25 Weight [down arrow] [up arrow] Extracellular fluid volume [down arrow] N, [up arrow] Jugular venous distention - -, + Hematocrit [up arrow] [down arrow] Blood urea nitrogen [up arrow] [down arrow] Creatinine [up arrow] [down arrow] Uric acid N, [up arrow] [down arrow] Bicarbonate [up arrow] [down arrow] Plasma albumin/ [up arrow] N protein concentration Blood pressure Low, [left and Normal right arrow] Central venous <6 >6 pressure, cm H2O Pulmonary wedge <8 >8 pressure, mmHg
08 Serum Osmolality, mOsm/kg 322 280-300 Osmolal gap (calculated (c)), mOsm/kg 56 -10 to 10 Serum alcohol screen (gas chromatography) Ethanol, mg/dL 128 Negative Acetone, mg/dL 37 Negative Isopropyl alcohol, mg/L 140 Negative Methanol, mg/L Negative Negative Ethylene glycol, mg/dL Negative Negative Urine drug screen (enzymatic immunoassay, Olympus AU400 EMIT) Opiates Positive Negative Tricyclic antidepressants Positive Negative Ethanol Positive Negative (a) Factors for converting conventional units of measure to SI units: bicarbonate, mEq/L x 1 = mmol/L; lactate, mg/dL x 0.
His serum osmolality was 320 mOsm/L and mannitol could no longer be given.
She had hyponatremia (124 mEq/L), with a low serum osmolality (249 mOsm/kg).
Serum osmolality is measured and also calculated with the variables serum glucose, sodium, and blood urea nitrogen (BUN) concentrations.
It has been also proposed that rapid change in serum osmolality is a causative factor for cerebral edema in DKA (7,8).
Serial chemistries showed a serum sodium level that had risen to 163 mmol/L, serum osmolality of 353 mOs/kg, and urine output ranging from 150 to 890 ml/hr.
10, an anion gap of 18, and a measured serum osmolality of 333 mOsm/kg, with a calculated value of 298 mOsm/kg.
1 mmol/L, and at that time the patient's serum osmolality was calculated to be 301 mOsm/kg.
SIADH is characterized by decreased serum osmolality with inappropriate urinary concentration (Larsen et al.

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