Importance of Glycolic Acid Analysis in Ethylene Glycol Poisoning

Abstract

The case conference entitled “Ethylene glycol poisoning: toxicokinetics and analytical factors affecting laboratory diagnosis” (1) provided a thorough review of many toxicological aspects involved in the diagnosis and monitoring of ethylene glycol (EG) poisoning. The authors stated that “the most serious clinical features observed in EG poisoning are due not to the parent compound but to the metabolites”. It was disappointing, therefore, that the authors did not include glycolic acid (GA) analysis in their investigations. Toxicologists first reported the importance of GA analysis in EG poisonings over 10 years ago (2)(3). The third case in this case conference was a diagnostic challenge to the authors because of repeated negative serum EG measurements. Based on our experience with GA analysis in many EG poisonings (4), the diagnosis of EG poisoning could have been made with serum GA analysis in case 3 without a renal biopsy. As stated in the conference, GA accounts for >90% of the anion gap in EG-poisoned patients (the anion gap in case 3 was 20 mmol/L). It was also mentioned that initial … aAuthor for correspondence. E-mail wolfb{at}mail.med.upenn.edu