Montgomery, AL – There have been enough complaints about the accuracy of prison drug testing that Corrections Commissioner Donal Campbell has said he will review the process. Inmates have complained that flawed results could threaten their ability to gain parole. University of Alabama at Birmingham forensic science professor Fred Smith specializes in drug testing. He says the screens used to test prisoners produce a small percentage of false positives. Smith says the errors occur because the second tests don't use a different method to confirm the initial results. Commissioner Campbell says his evaluation will examine drug testing throughout the corrections system. During the last fiscal year, the prison system performed about 121-thousand drug tests on prisoners and staff. More than 21 hundred of them tested positive for illegal drugs or alcohol.