USDTL Assisted Research
Field Testing the Microgenics DRI EtG assay for Georgia’s Treatment
Courts: A 3-Month Analysis of Screening and Confirmation Data
DeKalb County Drug Court, 556 N. McDonough Street, Decatur, Georgia 30030. The report was prepared for the Georgia Administrative Office of the Courts and Judicial Council Standing
Committee of Drug Courts. The study was conducted with the generous support of United States Drug Testing Laboratories, Inc.
Ethyl Glucuronide (EtG) is a direct biomarker of ethanol ingestion with a 2 to 5 day detection window in urine and is generally accepted to detect beverage ethanol consumption at or above a 90 percent sensitivity level. EtG’s superior detection window and sensitivity over conventional breath and urine ethanol detection methods has made it an increasingly popular assay for detection of participant alcohol use and relapse among Georgia’s Drug and DUI treatment courts. The introduction of the Microgenics DRI EtG assay was met with considerable interest by Georgia’s Drug and DUI Treatment Courts given its potential cost-savings and operational benefits. However, the limited public domain data exploring the screen’s field performance and relationship to mass spectrometry confirmation results prompted the DeKalb County Drug Court to undertake the present study with the participation of several partnering jurisdictions, including Cherokee, DeKalb, Fulton, and Gwinnett County treatment courts.
The primary goal of the study was to confirm the Microgenics DRI EtG assay’s sensitivity, specificity, and reliability in non-laboratory conditions. The study was conducted by comparing positive results at 500 ng/mL and 100 ng/mL to higher-order mass spectrometry confirmation results on the same sample. Although a relatively limited number of specimens tested positive at the 500 ng/mL cut-off, the Microgenics DRI EtG assay stood-up to LC/MS/MS in approximately 85% of confirmations. Conversely, the screen did not perform as well at a 100 ng/mL cut-off, yielding a 59% confirmation rate. A rather startling result from the study was that nearly 12% of screens sent for LC/MS/MS confirmation indicated the possibility of EtG breakdown between screen and confirmation. The results of the study suggest that the Microgenics DRI EtG assay performs at a satisfactory level of sensitivity, specificity and reliability at 500 ng/mL in nonlaboratory conditions.