Interference by Glycolic Acid in the Beckman Synchron Method for Lactate: A Useful Clue for Unsuspected Ethylene Glycol Intoxication

Falsely increased plasma lactate concentration due to ethylene glycol poisoning in 2 dogs

“…Interpretation of the extremely increased plasma lactate concentration in the 2 cases presented here was complicated as both animals were in circulatory shock on presentation and a lactic acidosis secondary to anaerobic metabolism was expected. The degree of hyperlactatemia present was extreme when measured on the ABL‐800 machine (> 30 mmol/L) and previous authors have suggested that such elevations should increase a clinician's index of suspicion for the presence of glycols interfering with the lactate measurement . Following resuscitation in Case 2 of this report, the dog was considered to have adequate perfusion and yet the ABL‐800 still reported persistent extreme hyperlactatemia.…”

“…Metabolites of EG can cause an artificial increase in lactate on many point‐of‐care analyzers as illustrated by the 2 cases presented here. There have been several reports of this issue in human medicine, including 1 case of EG intoxication that almost had an exploratory laparotomy due to concern for mesenteric ischemia as a cause of the increase in lactate concentration . Artifactual increase in lactate are not unique to EG toxicity as isoniazid, acetaminophen, and thiocyonate at high doses can cause artifactual increases in lactate concentration on some analyzers .…”

Ethylene glycol poisoning: a rare but life-threatening cause of metabolic acidosis--a single-centre experience

“…In 1968, Gabow et al [ 9 ] showed that patients with ethylene glycol poisoning often present with elevations in their serum lactate concentration. The question is whether such elevations of lactate levels (usually minor) are substantial or are likely errors of measurement of some laboratory instruments that cannot differentiate between lactate and glycolate, which is structurally similar to lactate and occurs when ethylene glycol is metabolized to glycolate [ 10 – 15 ]. Meng et al [ 16 ] recommend that elevated lactate concentrations on blood gas analysers should be confirmed by a chemistry analyser in the differential diagnosis of ethylene glycol poisoning.…”

Challenges in the diagnosis of ethylene glycol poisoning

“…Third, depending on which type of laboratory equipment is used, the lactate assay may be falsely elevated secondary to interference with the assay from glycolic acid. [83][84][85][86][87][88][89] It appears that glycolic acid may be responsible for this artefact due to structural similarity with lactate. 90 Analytical machines used for point-of-care testing have been associated with falsely elevated lactate measurements.…”

“…Some authors advocate measuring glycolic acid concentrations as another indirect indicator of ethylene glycol poisoning. 84,94 A technique for simultaneous detection of glycolic acid and ethylene glycol using gas chromatography has been described. 95 However, a laboratory which is unable to analyse ethylene glycol concentrations using gas chromatography would also not be in a position to process a glycolic acid concentration.…”