Question: how often are etg tests used?
Answer: Abstinence: EtG in hair (every 3 months), PEth in blood (covers 1 week) Social drinker: EtG in hair (every 3 months), PEth in blood (covers 1 month) Excessive drinker: EtG in hair (every 3 months), and CDT and/or PEth in blood (covers 1 month)