title: Interference of ethylene glycol with (L)-lactate measurement is assay-dependent.
abstract: BACKGROUND
  Metabolites of ethylene glycol (EG) can cross-react in l-lactate assays, leading to falsely elevated serum lactate levels in case of EG intoxication. In this study, we evaluated the effects of EG and its metabolites on routinely used lactate measuring methods.
  
  
  METHODS
  Serum aliquots were spiked with either l-lactate, EG or one of its metabolites (all 12.5 mmol/L): glyoxal, glycolate, glyoxylic acid or oxalate. An unspiked sample (l-lactate 2.6 mmol/L) served as a control. l-Lactate levels in these samples were measured in 31 national hospitals on 20 different analysers from nine manufacturers.
  
  
  RESULTS
  The l-lactate concentrations in the control sample and in the samples spiked with l-lactate, EG, glyoxal and oxalate provided correct results by all routinely used methods. However, the glycolate and glyoxylic acid spiked samples resulted in falsely elevated l-lactate concentration with all blood gas methods and with the majority of general chemistry methods using l-lactate oxidase.
  
  
  CONCLUSIONS
  The EG metabolites glycolate and glyoxylic acid were shown to falsely elevate l-lactate results with most of the currently used methods due to cross-reactivity with the oxidase enzyme. Falsely elevated l-lactate results can lead to misdiagnosis and inappropriate management of patients with EG intoxication.
authors.affiliation: Department of Clinical Chemistry, , Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands. a.tintu@erasmusmc.nl
authors.forename: Andrei
authors.initials: A
authors.lastname: Tintu
authors.forename: Ellen
authors.initials: E
authors.lastname: Rouwet
authors.forename: Henk
authors.initials: H
authors.lastname: Russcher
mesh_terms: D002849:Chromatography, Gas / Q000592:standards*; D003951:Diagnostic Errors; D057075:Enzyme Assays / Q000592:standards*; D019855:Ethylene Glycol / Q000097:blood* / Q000506:poisoning; D005189:False Positive Reactions; D006016:Glycolates / Q000097:blood*; D006037:Glyoxal / Q000097:blood; D006038:Glyoxylates / Q000097:blood*; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000592:standards; D019815:Oxalic Acid / Q000097:blood
chemical_list: D006016:Glycolates; D006038:Glyoxylates; C031149:glycolic acid; D019344:Lactic Acid; D006037:Glyoxal; D019815:Oxalic Acid; D006899:Mixed Function Oxygenases; C021497:lactate 2-monooxygenase; D019855:Ethylene Glycol; C031150:glyoxylic acid