Find the analyte, value, units, and cutoff
Confirm that the report says EtG or ethyl glucuronide and uses ng/mL. Then compare the measured result with the stated cutoff. Do not apply a 500 ng/mL interpretation to a report using 100 ng/mL.
Positive, negative, and below-reportable results
A positive result meets the reporting rule; a negative result does not. Some reports show a number below the cutoff while others say 'not detected.' These formats may reflect different laboratory reporting limits.
Why creatinine and EtS matter
Urine creatinine helps indicate how concentrated or dilute a sample is. EtS is a second direct ethanol metabolite and may be used as corroborating evidence. Neither turns the report into an exact drinking timeline.
Questions to ask about an EtG report
- What cutoff and analytical method were used?
- Was the screen confirmed by a more specific method?
- Were EtS and creatinine measured?
- How long after the possible exposure was the sample collected?
- What policies govern incidental exposure and disputed results?
Evidence and limitations
This guide summarizes primary research and public-health guidance. Group-level findings cannot predict one person's result.