Relationship between serum glycolate and falsely elevated lactate in severe ethylene glycol poisoning.
In the setting of ethylene glycol (EG) poisoning, a falsely elevated serum lactate concentration is suggested to be an assay cross-reaction with glycolate, but a concentration-dependent relationship has never been identified. We correlate serum lactate and glycolate concentrations in a case of severe EG poisoning. Serial EG [by gas chromatography (GC)], glycolate (derivatized to methyl glycolate, analysis by GC), and lactate (both enzymatic spectrophotometry and GC) concentrations were correlated at five time points. False-positive lactate was confirmed by absence of lactate on GC analysis. The correlation coefficient (Pearson's r) between lactate (by enzymatic spectrophotometry) and glycolate was 0.984 and was statistically significant (p < 0.01). The mean lactate/glycolate conversion factor was 2.58 +/- 0.95. We demonstrate the linear correlation between falsely elevated serum lactate and glycolate concentrations in a case of severe EG poisoning. Our data provide further support to the belief that the lactate assay may cross-react with glycolate in EG poisoning.
New York City Poison Control Center, Department of Health and Mental Hygiene, New York, New York, USA. alex.manini@mountsinai.org
Alex F
AF
Manini
Robert S
RS
Hoffman
Kenneth E
KE
McMartin
Lewis S
LS
Nelson
D000368:Aged; D001784:Blood Gas Analysis / Q000295:instrumentation*; D002849:Chromatography, Gas; D019855:Ethylene Glycol / Q000097:blood / Q000506:poisoning*; D005189:False Positive Reactions; D006016:Glycolates / Q000097:blood*; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D011041:Poisoning / Q000175:diagnosis
D006016:Glycolates; C031149:glycolic acid; D019344:Lactic Acid; D019855:Ethylene Glycol