 Immunoassay strips containing antibodies bind to components of the different drugs.A number of independent studies examine the efficacy of the DrugWipe, particularly for its lack of sensitivity for detecting Cannabis (delta-9-thc) which the Australian National Health Survey 2009 listed as the most frequently used illicit drug at 10.4% with 36% smoking at least once a week or more in 2016.Independent field testing of the DrugWipe in Finland recorded a high rate of false negatives, particularly for Cannabis, this is where a person tests negative however had recently used  14.4%.