Tenn. Code Ann. § 41-1-119: Urinalysis drug screening program

(a) A urinalysis drug screening program shall be established within the department of correction. Every thirty (30) days, a urine sample shall be taken from each of twenty-five (25) prison inmates selected at random who are confined in each state correctional institution; and a urinalysis shall be performed to determine the presence of drugs. A positive result shall be investigated by the department to determine whether the result emanated from the prison inmate's use of legally prescribed medicine or whether it resulted from the use of illegal drugs.

(b) The commissioner has the authority to promulgate necessary rules and regulations to implement this section pursuant to the Uniform Administrative Procedures Act, compiled in title 4, chapter 5. These rules shall provide detailed guidelines and standards for the manner in which the urine samples are taken and the manner in which the investigations required by this section are conducted.