DETERMINATION OF BLOOD ETHANOL LEVELS: COMPARISON OF ENZYMATIC AND GAS CHROMATOGRAPHIC METHODS

Öz

Objective: Forensic and clinical laboratories determine blood alcohol concentrations (BAC) using gas chromatography–head space, and enzymatic ethanol assay methods. However, the use of enzymatic ethanol assays is still controversial. Several authors have reported that increased concentrations of lactate dehydrogenase might cause false-positive results with enzymatic ethanol assays. This study was designed to compare the Roche® enzymatic method with the reliable conventional gas chromatographic method. Methods: The blood samples collected from 20 voluntary individuals (3 females and 17 males) were analyzed by both methods. A control group was constituted from 10 healthy individuals that were non-users of alcohol. Results: Blood LDH levels of all participants were varying between 294-932 U/L. A significant correlation related with the effect of LDH level on BAC was not detected since the LDH levels were in normal range. The present study shows significant quantitative difference in detected blood ethanol levels of the experimental group between the enzymatic and gas chromatographic methods. All samples of alcohol users were positive and the percentage difference between BAC obtained by the enzymatic versus the GCHS method ranged from -166 to +17%. Nineteen (95%) in 20 positive samples showed lower detected ethanol values with the enzymatic method compared to GC-HS analysis. Despite the fact that ethanol was found to be negative in all samples of the control group with GC-HS method, enzymatic method gave false positive results for two samples (10%) of the control group. Conclusion: GC-HS still remains as a specific, accurate and reliable method for determination of ethanol levels.

Anahtar Kelimeler

• blood alcohol concentration
• enzymatic ethanol assay
• gas chromatography-head space

Kaynakça

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