Why do EtG cut-off values vary at different labs?
Various cut-off levels (100, 250, 500, or 1000 ng/mL) are suggested for use in EtG testing. Any EtG level over 100 ng/mL and EtS level over 25 ng/mL indicates exposure to ethanol. In order to provide alcohol abstinence programs with the most clinically relevant answer to whether or not recent ethanol ingestion has occurred, using a 100 ng/mL cut-off for EtG and a 25 ng/mL cut-off for EtS detection is the best and most definitive test available to answer this question. RTL uses a 100 ng/mL EtG cut-off level and a 25 ng/mL EtS cut-off level.
