Acceptability and accuracy of oral fluid drug testing for patients on methadone maintenance

Methadone maintenance is currently the predominant form of opioid substitution treatment available in the Republic of Ireland. Prescribing decisions currently involve urine testing for drug use. Urine testing may involve provision of a supervised sample in some circumstances, despite recommendations made in 2010 to abandon this practice. This project aims to evaluate the accuracy and acceptability of oral fluid testing for patients on methadone maintenance and also gather patient views on their treatment. Patients attending for methadone maintenance at 4 general practices were invited to take part in this study, which involved taking an additional oral fluid test and a questionnaire. Fifty-five patients agreed to participate. Fifty-two (95%) found the oral fluid test acceptable, and almost two-thirds would prefer to see it used instead of urine testing. Oral fluid provided similar results to urine testing for all drugs except benzodiazepines. Self-report identified cocaine and opiate use not detected by oral fluid or urine testing. This study presents evidence that oral fluid testing is acceptable to most patients. While oral fluid testing was inferior to urine testing for benzodiazepines, it may have an adjunctive role to play in methadone maintenance provision. Patients reported more negative than positive aspects of methadone maintenance.