Border Security: CBP Has Taken Actions to Help Ensure Timely and Accurate Field Testing of Suspected Illicit Drugs, Report to the Chairwoman, Caucus on International Narcotics Control, U.S. Senate [open pdf - 1MB]
From the Highlights: "Within the Department of Homeland Security, CBP [U.S. Customs and Border Protection] reported seizing approximately 830,000 pounds of drugs in fiscal year 2020. When CBP officers and agents encounter suspected illicit drugs, they conduct a presumptive field test. A positive test result is one factor CBP uses to establish probable cause for an arrest or seizure. GAO [Government Accountability Office] was asked to review issues related to CBP's field drug testing. This report examines (1) CBP's policies and procedures for testing suspected illicit drugs in the field; (2) available data on CBP's field drug testing; and (3) CBP's efforts to help ensure timely and accurate test results."
Government Accountability Office: https://www.gao.gov/