It is more than likely the cut off value used for the test.
The 100 would show as you have failed easier than the 500 because it would take 500ng instead of 100ng to pop positive.
Both EtG and EtS are minor but important metabolites of alcohol (ethanol) (from a monitoring perspective), because they are more slowly eliminated from the body than alcohol itself and can thus be used to better document abstinence and detect alcohol relapse earlier. One standard drink, in an average person, can be detectable for about 24 hours (using the lowest cutoffs of 100ng/ml for EtG and 25ng/ml for EtS), whereas, urine alcohol will disappear following one drink within about 4 – 6 hours. After binge drinking EtG and/or EtS can be detected in urine for several days or more.
if the testers have the money and flexibility to evaluate low positives and deal with more “gray zone” cases, in which it is difficult to know what caused the positive, but wishes to detect relapses as early as possible, then a low cutoff is preferable.
Some labs have reported that up to ½ of their positive EtG tests are between 100-500ng/ml.
Setting a higher cutoff may cause less stress and confusion but fewer drinking episodes will be detected. Each program must weigh their own policies, flexibility, and desire for early detection to determine what cutoff they wish to use.
Cutoffs for EtG commonly available include: 100, 250, 500, and 1,000ng/ml.
The 100 would show as you have failed easier than the 500 because it would take 500ng instead of 100ng to pop positive.
Both EtG and EtS are minor but important metabolites of alcohol (ethanol) (from a monitoring perspective), because they are more slowly eliminated from the body than alcohol itself and can thus be used to better document abstinence and detect alcohol relapse earlier. One standard drink, in an average person, can be detectable for about 24 hours (using the lowest cutoffs of 100ng/ml for EtG and 25ng/ml for EtS), whereas, urine alcohol will disappear following one drink within about 4 – 6 hours. After binge drinking EtG and/or EtS can be detected in urine for several days or more.
if the testers have the money and flexibility to evaluate low positives and deal with more “gray zone” cases, in which it is difficult to know what caused the positive, but wishes to detect relapses as early as possible, then a low cutoff is preferable.
Some labs have reported that up to ½ of their positive EtG tests are between 100-500ng/ml.
Setting a higher cutoff may cause less stress and confusion but fewer drinking episodes will be detected. Each program must weigh their own policies, flexibility, and desire for early detection to determine what cutoff they wish to use.
Cutoffs for EtG commonly available include: 100, 250, 500, and 1,000ng/ml.
