Ethylene Glycol (By Immunoassay)
Label Mnemonic: EGLYC
Epic Lab Code: LAB7453
Downtime Form: A-1a Miscellaneous Request
Chemistry
6240 RCP
356-3527
Specimen(s):
Plasma
Collection Medium:
Plasma Separator Tube 4.5 mL
Minimum:
3 mL whole blood in light green top tube or ONE Microtainer®
Reference Range:
Clinical toxicity may be seen with plasma concentrations of >10 mg/dL. Anion gap and arterial blood gas determinations may be useful in determining conversion of ethylene glycol to toxic metabolites.

Critical value: Ethylene glycol 10 mg/dL or greater
Comments:
This test uses an enzymatic assay for measurement of ethylene glycol (see Reference #3).

Will be reflexively ordered after Ethanol/Volatiles Screen with an unexplained osmolar gap > 15. May also be directly ordered in cases of suspected ethylene glycol ingestion. This procedure individually quantitates ethylene glycol.

This procedure is not suitable for the detection of other toxic alcohols including methanol and isopropanol. If methanol or isopropanol ingestion is suspected, see test "Alcohol, Plasma." Ethylene glycol is commonly found in many automobile antifreezes.
Test Limitations:
Icterus: No significant interference from bilirubin up to an I index of 15.

Lipemia: No significant interference from lipemia up to an L index of 1000.

Hemolysis: No significant interference from hemolysis up to an H index of 200.

Two compounds can interfere with the ethylene glycol enzymatic assay: 2,3-butanediol and propylene glycol. 2,3-Butanediol is a compound most commonly found in individuals that chronically ingest large amounts of ethanol. Concentrations of 2,3-butanediol in the range of 0.1 to 7 mg/dL have been observed in studies of patients with history of heavy consumption of ethanol. 2,3-Butanediol serum levels usually decline within 8-12 hours of abstaining from ethanol (see ref. 2). 2,3-Butanediol plasma concentrations in excess of 5 mg/dL have the potential for producing a positive results of ~10 mg/dL on the ethylene glycol enzymatic assay. Such high plasma concentrations of 2,3-butanediol are likely quite rare and would be expected only in individuals with history of very heavy acute and chronic consumption of ethanol.

Propylene glycol is found as a diluent in a number of intravenous medications (e.g., lorazepam, diazepam, etomidate), in some activated charcoal preparations, and also in a limited number of automobile antifreezes. If propylene glycol interference is detected, the ordering provider is notified and the ethylene glycol assay resulted as "Propylene glycol present. Unable to determine presence or absence of ethylene glycol due to interference."

Please contact pathology resident at #3404 with any questions or to determine if further analysis by gas chromatography is indicated.

References:
(1) Eder AF et al. Ethylene glycol poisoning: toxicokinetic and analytical factors affecting laboratory diagnosis. Clin Chem 44: 168- 177, 1998.

(2) Felver ME et al. The presence of 2,3-butanediol in the blood of chronic alcoholics admitted to an alcohol treatment center. Adv Exp Med Biol 132: 229-235, 1980.

(3) Juenke JM et al. Rapid and specific quantification of ethylene glycol levels: adaptation of a commercial enzymatic assay to automated chemistry analyzers. Am J Clin Pathol 136: 318-324, 2011.

(4) Lynd LD et al. An evaluation of the osmole gap as a screening test for toxic alcohol poisoning. BMC Emerg Med 8: 5, 2008.

(5) Krasowski MD et al. A retrospective analysis of glycol and toxic alcohol ingestion: utility of anion and osmolal gaps. BMC Clin Pathol 12: 1, 2012.
Methodology:
Enzymatic Assay using glycerol dehydrogenase
CPT Code:
80320