osmolal gap


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Related to osmolal gap: osmolar gap

osmolal gap

[ozmōl′əl]
a difference between the observed and calculated osmolalities in serum analysis. The calculated osmolar values include sodium concentration multiplied by 2, plus glucose and blood urea nitrogen.

osmolal gap

The difference between the measured osmolality of the plasma, and the calculated osmolality of the plasma (plasma glucose/18 + blood urea nitrogen/2.8 + sodium*2). A gap is present when the difference exceeds 10 mmol/kg of water. Osmolal gaps are present when unmeasured osmotically active solutes, such as toxins, e.g., methanol or ethylene glycol, are present in the plasma.
See also: gap

osmolal

adjectival form of mole, a one osmolal solution contains 1 mole of solute in 1 L of water.

osmolal gap
difference between the measured plasma osmolality and the osmolality calculated from the plasma concentration of normally measured solutes.
References in periodicals archive ?
In a patient with an increased osmolal gap and normal anion gap, can EG poisoning be ruled out?
Can a normal osmolal gap be used to determine when fomepizole therapy should be discontinued?
Traditionally, such poisoning is recognized by ethylene glycol's tendency to cause an increase in the serum osmolal gap with and without an increase in the serum anion gap.
The metabolic acidosis and increased serum osmolal gap are also not always present together.
Excess osmolal gap in diabetic ketoacidosis explained.
In a patient with an established metabolic acidosis from toxic alcohol ingestion, a normal or low osmolal gap can occur if blood is sampled after the volatile alcohols have been converted to the acid metabolites (59).
In general, this alcohol usually appears as the cause of a mild metabolic acidosis and source of developing osmolal gap in the intensive care unit setting (63,64).
The difference between measured and calculated osmolality, the osmolal gap, results from the presence of other solutes in serum, which are not considered in the above formula.
As ethylene glycol is being metabolized or removed by dialysis, its contribution to the osmolal gap diminishes because the accumulating acidic, negatively charged metabolites do not contribute to the osmolal gap [30].