When implementing zero-tolerance alcohol testing policy a common tendency is to classify any alcohol test result greater than 0.000 as a positive test. However, best practice suggests setting a cut-off level higher than 0.000. Here are our recommendations for zero-tolerance cut-off levels, and the rationales to support them.

Workplace
We recommend 0.020 cut-off as a positive test for workplace testing, with any result below 0.020 (0.019 and below) classified as a negative test. 0.020 is the cut-off level used by the U.S. Department of Transportation (DOT) workplace alcohol testing program. DOT alcohol testing policy and protocol is the gold standard for workplace alcohol testing. A company that models their policy after the DOT regulations can feel secure that their policy is very defensible.

Alcohol Treatment Programs
For alcohol abuse treatment programs we recommend 0.010 cut-off as a positive test, with any result blow this (0.009 and below) classified as a negative test. An alcohol test result of 0.010 on an evidential quality Alco-Sensor FST indicates the presence of alcohol with a high degree of confidence. Because the consequences of positive tests in alcohol treatment programs are usually not as serious as in workplace testing we are comfortable recommending a lower cut-off level for alcohol treatment programs. A lower cut-off level that detects more drinkers better meets the needs of treatment programs.

Why have a cut-off level at all? 
Standard laboratory testing protocols establish cut-off levels for every substance. Cut-off levels are set high enough to give a high level of confidence, ruling out the possibility of false positives. Cut-off levels must also be set high enough to accommodate a reasonable margin of error in the testing device. Therefore, zero is never used as a cut-off level in laboratory testing.