Clinical Utility of Institution-Based Serum Ethylene Glycol Measurement in Guiding Cessation of Hemodialysis for Toxin Removal: A Case Report

Ethylene glycol (EG) poisoning is a potentially life-threatening intoxication that can cause neurological toxicity, metabolic acidosis, acute kidney injury, and multiorgan failure. Although serum EG concentrations are useful for guiding treatment, timely direct measurement is not routinely available at many institutions, particularly in Japan. Here, we report on a 33-year-old man who presented approximately 30 h after inadvertently ingesting about 150 mL of EG-containing antifreeze. On admission, serum creatinine was 3.95 mg/dL, and neither the anion gap nor the osmolar gap was increased. Fomepizole and hemodialysis were initiated. To support decisions regarding treatment duration, stored serum samples were analyzed in collaboration with our institutional clinical pharmacology center using liquid chromatography–tandem mass spectrometry. Serum EG concentrations were below the operational lower limit of quantification (LLOQ) of 5 mg/dL, providing objective evidence to discontinue hemodialysis for toxin removal after the third session. The patient subsequently showed neurological improvement, whereas renal dysfunction persisted. This case demonstrates the clinical utility of institution-based analytical toxicology in measuring serum EG and supporting evidence-based decisions regarding extracorporeal treatment.