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An enzymatic assay for the detection of glycolic acid in serum as a marker of ethylene glycol poisoning.
Ther Drug Monit. 2013 Dec; 35(6):836-43.TD

Abstract

BACKGROUND

Ingestion of ethylene glycol is a relatively rare event but one with potentially lethal consequences. Early diagnosis and appropriate treatment are essential. However, diagnosis of poisoning can only be confirmed definitively by the measurement of ethylene glycol and/or its metabolites, usually performed by gas chromatographic methods. These methods are complex, requiring specialized equipment and expertise, and are often not available on an emergency basis.

METHODS

A quick, simple, and inexpensive enzymatic assay has been developed to detect glycolic acid, the major metabolite of ethylene glycol and the main cause of the resulting metabolic acidosis. In this assay, glycolic acid is converted to glyoxylic acid by glycolate oxidase, with the production of hydrogen peroxide, which is converted to a quinoneimine dye for spectrophotometric detection.

RESULTS

The assay has a functional sensitivity of 26 mg/L and coefficients of variation less than 13% (interassay) and less than 10% (intra-assay). No significant interference was observed for a range of compounds, and a comparison with a gas chromatography-mass spectrometry method gave clinical sensitivity of 86% and clinical specificity of 92%. Stability of enzyme solutions was increased by the use of an alternative buffer, in which greater than 90% of the original activity was retained after storage at -20°C.

CONCLUSIONS

As ethylene glycol poisoning is a medical emergency, there is a need for a screening test to minimize delays in diagnosis. The assay we describe is a simple and effective way to detect ethylene glycol poisoning, enabling earlier initiation of appropriate therapy and improving patient outcomes.

Authors+Show Affiliations

Department of Clinical Biochemistry, Aintree University Hospital, Liverpool, UK.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

24263643

Citation

Hanton, Sally L., and Ian D. Watson. "An Enzymatic Assay for the Detection of Glycolic Acid in Serum as a Marker of Ethylene Glycol Poisoning." Therapeutic Drug Monitoring, vol. 35, no. 6, 2013, pp. 836-43.
Hanton SL, Watson ID. An enzymatic assay for the detection of glycolic acid in serum as a marker of ethylene glycol poisoning. Ther Drug Monit. 2013;35(6):836-43.
Hanton, S. L., & Watson, I. D. (2013). An enzymatic assay for the detection of glycolic acid in serum as a marker of ethylene glycol poisoning. Therapeutic Drug Monitoring, 35(6), 836-43. https://doi.org/10.1097/FTD.0b013e31828f019c
Hanton SL, Watson ID. An Enzymatic Assay for the Detection of Glycolic Acid in Serum as a Marker of Ethylene Glycol Poisoning. Ther Drug Monit. 2013;35(6):836-43. PubMed PMID: 24263643.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - An enzymatic assay for the detection of glycolic acid in serum as a marker of ethylene glycol poisoning. AU - Hanton,Sally L, AU - Watson,Ian D, PY - 2013/11/23/entrez PY - 2013/11/23/pubmed PY - 2014/7/18/medline SP - 836 EP - 43 JF - Therapeutic drug monitoring JO - Ther Drug Monit VL - 35 IS - 6 N2 - BACKGROUND: Ingestion of ethylene glycol is a relatively rare event but one with potentially lethal consequences. Early diagnosis and appropriate treatment are essential. However, diagnosis of poisoning can only be confirmed definitively by the measurement of ethylene glycol and/or its metabolites, usually performed by gas chromatographic methods. These methods are complex, requiring specialized equipment and expertise, and are often not available on an emergency basis. METHODS: A quick, simple, and inexpensive enzymatic assay has been developed to detect glycolic acid, the major metabolite of ethylene glycol and the main cause of the resulting metabolic acidosis. In this assay, glycolic acid is converted to glyoxylic acid by glycolate oxidase, with the production of hydrogen peroxide, which is converted to a quinoneimine dye for spectrophotometric detection. RESULTS: The assay has a functional sensitivity of 26 mg/L and coefficients of variation less than 13% (interassay) and less than 10% (intra-assay). No significant interference was observed for a range of compounds, and a comparison with a gas chromatography-mass spectrometry method gave clinical sensitivity of 86% and clinical specificity of 92%. Stability of enzyme solutions was increased by the use of an alternative buffer, in which greater than 90% of the original activity was retained after storage at -20°C. CONCLUSIONS: As ethylene glycol poisoning is a medical emergency, there is a need for a screening test to minimize delays in diagnosis. The assay we describe is a simple and effective way to detect ethylene glycol poisoning, enabling earlier initiation of appropriate therapy and improving patient outcomes. SN - 1536-3694 UR - https://www.unboundmedicine.com/medline/citation/24263643/An_enzymatic_assay_for_the_detection_of_glycolic_acid_in_serum_as_a_marker_of_ethylene_glycol_poisoning_ L2 - https://doi.org/10.1097/FTD.0b013e31828f019c DB - PRIME DP - Unbound Medicine ER -