Assessing the impacts of a drug testing error in a correctional setting

Urinalysis screening tests are a component of substance use treatment programs in carceral settings. Although results of these tests are meant to be used by physicians to guide treatment, they may also influence parole suitability determinations. Utilizing administrative datasets from the California Department of Corrections and Rehabilitation (CDCR), the present analysis quantifies the scale and institutional distribution of a reported reagent error in opiate urinalysis testing in California prisons' Medication-Assisted Treatment (MAT) program from April to July 2024. Statistical methods including differences-in-differences (DD), interrupted time-series analysis, and structural break tests were applied to monthly aggregated and individual-level test data. Estimated excess positive opiate tests ranged from 4490 to 5839, with a median estimate of 5425. Facility-specific increases ranged from approximately 2 to over 16 percentage points above baseline rates. Given the potential impact of a positive urinalysis screening test result on incarcerated individuals' parole outcomes, these findings underscore the need for improved quality controls and confirmatory testing in correctional settings. Additionally, remedial reviews of parole actions influenced by potentially erroneous results may be warranted.