Laboratory Diagnosis of Ethylene Glycol Poisoning

Abstract

The major toxic alcohols that pose a risk to human health and for which measurement of levels is requested from the clinical laboratory include ethanol, ethylene glycol, isopropanol, and methanol. Most clinical laboratories are equipped to accurately quantitate ethanol levels, mainly by an enzymatic assay on an automated chemistry analyzer platform. However, the measurement of the other 3 alcohols is more challenging.1,2 Some relevant laboratory tests that assist in the differential diagnosis are listed in Table 1. An increase in the osmolal gap is evident in the presence of all of the alcohols. In addition, methanol, ethanol, and ethylene glycol also result in an increase in metabolic acidosis with an increased anion gap, separating them from isopropanol. A relevant clue to isopropanol ingestion is positivity for acetone in the urine or blood without attendant hyperglycemia. In addition to an increase in the osmolal gap and anion gap acidosis, ethylene glycol ingestion can result in a positive urine analysis for the presence of calcium oxalate crystals (monohydrate and dihydrate) because it is converted to oxalate, which can chelate calcium and result in hypocalcemia. However, it needs to …