What is the normal osmolal gap?
A normal osmol gap is < 10 mOsm/kg .
How is osmolal gap measured?
The osmolality gap (OG) is an indication of unmeasured solute in the blood. It is determined by the measured osmolality (MO) minus the calculated osmolality (CO)….Osmolality Gap Calculator.
| Plasma sodium concentration: | mmol/L |
|---|---|
| Measured Osmolality, plasma: | mOsm/kg H2O |
| Measured ETOH, plasma: | mg/dL |
| Osmolality Gap: |
What is the significance of osmolar gap?
It is important to recognize that neither the presence nor absence of an osmolar gap can be used to confirm or exclude a toxic alcohol ingestion. With both methanol and ethylene glycol, the alcohols are metabolized from an alcohol to an aldehyde, and ultimately to an acid.
What does high osmolar gap mean?
High unexplained osmolar gaps indicate the possible presence of a toxic compound other than ethanol (ethylene glycol, methanol, acetone, isopropanol, or propylene glycol).
What are four clinical conditions associated with an abnormal osmolal gap?
Clinicians should be aware of the common causes of elevated osmolal gap other than toxic alcohols, including alcoholic ketoacidosis, renal failure, shock, diabetic ketoacidosis, and recent mannitol administration.
What can cause Pseudohyponatremia?
The most common cause of pseudohyponatremia is due to severely elevated levels of cholesterol. [2] In serum blood samples taken from patients with severe hypertriglyceridemia, the sample may appear overtly lipemic, hyper viscous, or discolored from the overwhelming presence of insoluble triglycerides.
What is an osmotic gap?
Stool osmotic gap is a measurement of the difference in solute types between serum and feces, used to distinguish among different causes of diarrhea. Feces is normally in osmotic equilibrium with blood serum, which the human body maintains between 290–300 mOsm/kg.
Which of the following may cause osmolar gap?
Ethanol, methanol, ethylene glycol (used in anti-freeze solutions), isopropanol, and propylene glycol (used as a vehicle with some drugs e.g. lorazepam) are solutes that cause an elevated osmolar gap.
What does negative osmolar gap mean?
If we detect an elevated osmolal gap, our management is exactly the same. A negative result decreases the post-test probability of toxic alcohol exposure to 23%. Therefore, it is possible that a normal osmolal gap could be falsely reassuring in a patient with high pre-test probability of toxic alcohol ingestion.
What does the osmotic gap mean?
Stool osmotic gap is a measurement of the difference in solute types between serum and feces, used to distinguish among different causes of diarrhea. A normal gap is between 50 and 100 mOsm/kg, corresponding to the concentration of other solutes such as magnesium salts and sugars.
How does hyperlipidemia and Hyperproteinemia cause pseudohyponatremia?
In states of hyperproteinemia or hyperlipidemia, there is an increased mass of the nonaqueous components of serum and a concomitant decrease in the proportion of serum composed of water. Thus, pseudohyponatremia results because the flame photometry method measures sodium concentration in whole plasma.
Do you code pseudohyponatremia?
As such, pseudohyponatremia cannot be coded, and coding efforts should focus on identifying the inciting cause.
When to use osmolal gap and osmolar gap?
Because the calculated osmol gap can therefore be a conflation of both terms (depending on how it is derived), neither term (osmolal gap nor osmolar gap) may be semantically correct. To avoid ambiguity, the terms “osmolal” and “osmolar” can be used when the units of molality or molarity are consistent throughout the calculation.
Can a patient acquire ethylene glycol with a low osmolal gap?
Indeed, if the patient’s baseline osmolal gap was low at baseline (say, -8 mOsm/L), then the patient could acquire an ethylene glycol level >100 mg/dL despite a normal osmolal gap. The osmolal gap will be elevated by any uncharged molecules in the blood or any non-sodium cations in the blood.
How is the osmol gap of urea calculated?
Calculated osmolality = 2 x Na + Glucose/18 + Urea/6. A normal osmol gap is < 10 mOsm/kg . Explanation of units. Since laboratories measure serum solutes in terms of freezing point depression, the reported units are properly units of osmolality. When a measure of serum solutes is calculated, it is often done in units of osmolarity.
What does the unexplained osmolar gap in epic mean?
The osmolar gap (OSMOL GAP in Epic) uses formula (2) above. The unexplained osmolar gap (UOSMOL GAP in Epic) uses formula (4) above. High unexplained osmolar gaps indicate the possible presence of a toxic compound other than ethanol (ethylene glycol, methanol, acetone, isopropanol, or propylene glycol).