CAP TODAY Pathology/Laboratory Medicine/Laboratory Management
Editor: Deborah Sesok-Pizzini, MD, MBA, professor, Department of Clinical Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, and chief, Division of Transfusion Medicine, Children’s Hospital of Philadelphia.
Evaluation of ethanol interference on routine biochemical tests
March 2019—Ethanol, a central nervous system depressant widely consumed in many societies, is metabolized in the liver through multiple enzymatic pathways. If the liver’s capacity is exceeded, the excess alcohol will flood into the systemic circulation. Consequently, alcohol has the potential to interfere with laboratory tests and lead to uncertainty about the measurement results. The medical literature contains limited information about alcohol as a test interferent. The author conducted a study of the potential of alcohol to interfere with routine biochemical tests. He used serum pools from blood samples collected from patients seeking treatment at the emergency department. The author added ethanol, or ethyl alcohol, to the samples, and the final concentrations were negative, 50 mg/dL, 100 mg/dL, 200 mg/dL, and 400 mg/dL. The samples were divided into 20 equal portions, and routine biochemical tests were performed on each portion. The coefficient of variation, bias, and total error values were calculated for the measured parameters. The author found that alanine aminotransferase and lactate dehydrogenase activities decreased in proportion to ethanol level, causing false low results. High negative biases suggested dose-dependent negative interference. The total error values calculated for direct bilirubin and urea were higher than the allowable total error reported in the CLIA regulations. For direct bilirubin, it was observed that the cause of this shift was due to the increase in coefficient of variation values. The author concluded that ethanol may interfere with some biochemical tests, and the most prominent effect was observed for lactate dehydrogenase and alanine aminotransferase. Because clinical laboratory tests help drive clinical decision-making, awareness of potential interference is important. The author noted that the study findings would be valid for the selected samples and methods used in the analysis. Similar studies using other test methods and different automated instruments would be necessary to collect additional interference data.
Gumus A. Evaluation of ethanol interference on routine biochemical tests. Am J Clin Pathol. 2018;150:507–511.
Correspondence: Dr. Alper Gumus at dralpergumus@gmail.com