Ethylene glycol is an alcohol used in antifreeze that can cause serous toxicity if ingested. The concentration of ethylene glycol can be estimated from the osmolal gap.
Chemical name: 1,2-ethanediol, dihdroxyethane
Molecular weight of ethylene glycol: 62.07 g
guess at SIU: 1 mg/dL = 0.161 mmol/L; 1 mmol/L = 6.211 mg/dL
half-life: 3-6 hours
volume of distribution: 0.8 L/kg
NOTE: Estimating ethylene glycol concentration from the osmolal gap is applicable soon after ingestion. Ethylene glycol is metabolised to glycolic acid and other toxic metabolites which also will affect the osmolal gap. After a period of time the osmolal gap may still be elevated even though the measured concentrations of ethylene glycol are low; however, the estimates using the equations may give an indication of what the ethylene glycol concentration was before it was metabolised.
Common Equation for the Serum Osmolal Gap
predicted osmolality in mOsm per Kg H2O =
= (2 * (serum sodium concentration in mEq/L)) + ((serum glucose in mg/dL) / 18) + ((serum BUN in mg/dL) / 2.8)
serum osmolal gap =
= (measured osmolality) – (predicted osmolality)
Equation of Fligner et al for Serum Osmolal Gap
predicted osmolality in mOsm per Kg H2O =
= (1.86 * (serum sodium concentration in mEq/L)) + ((serum glucose in mg/dL) / 18) + ((serum BUN in mg/dL) / 2.8)
serum osmolal gap =
= (measured osmolality) – ((predicted osmolality) / 0.93)
Ethylene Glycol Based on Cadnapaphornchai et al
osmolal gap =
= (0.14 * (ethylene glycol in mg/dL)) + 0.35
ethylene glycol in mg/dL =
= (7.14 * (osmolal gap)) – 2.5
Ethylene Glycol Based on Chemical Formula
ethylene glycol in mg/dL =
= (osmolal gap) * 6.207
ethylene glycol in mmol/L =
= (osmolal gap)
