What is the role of lab testing in the diagnosis of ethylene glycol (EG) toxicity?

Updated: Dec 05, 2017
  • Author: Daniel C Keyes, MD, MPH; Chief Editor: Sage W Wiener, MD  more...
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Patients who ingest ethylene glycol may initially have few, if any, metabolic disturbances. Serum concentrations of ethylene glycol may be measured; however, at most health care facilities, these results are not available for 2 or more days. Thus, ethylene glycol concentrations are often not determined early enough to be useful in emergency treatment, though they should still be sent to confirm the diagnosis.

For institutions that frequently treat ethylene glycol toxicity cases, in-hospital rapid laboratory confirmation may become cost-effective because of the institutional cost-benefit ratio evaluation that compares therapy with fomepizole, ethanol, and hemodialysis. Emergency departments located in larger metropolitan areas may negotiate availability of this test at regional clinical laboratories. It is important to check on this availability at your own clinical site.

The classic laboratory profile of ethylene glycol ingestion is an early osmolar gap (the ethylene glycol serves as an unmeasured osmole) that disappears as an anion gap metabolic acidosis develops (as the ethylene glycol is converted into its acidic derivatives). However, there is a wide range of normal osmolar gaps, and even patients with early presentations after consequential ethylene glycol ingestions may have a normal osmolar gap, so it should never be used to exclude toxicity. Listed below are laboratory tests that will be useful in the setting of ethylene glycol ingestion.

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