P130 An audit of urinary drug screening use in multiple sleep latency and maintenance of wakefulness testing in an Australian tertiary centre

Multiple sleep latency test (MSLT) and maintenance of wakefulness test (MWT) are objective measures of excessive daytime sleepiness, used in diagnosing and monitoring patients with sleep disorders. MSLT and MWT can be affected by substances such as psychotropics, stimulants, opioids and sedatives. Recent studies demonstrate high prevalence of positive urine drug screening (UDS) results in patients undergoing MSLT and MWT. We retrospectively audited patients who underwent UDS with MSLT/MWT at a tertiary centre from 1st January 2019 to 1st January 2020. The following data was collected: MSLT/MWT/UDS results, sleep disorder diagnosis/es, return to driving/work after testing and pre-existing and subsequent prescription of stimulants/wakefulness-promoting agents/psychotropics/sodium oxybate. Our cohort featured 32 patients (23 female). 29 MSLTs and 3 MWTs were performed. Median age was 31 years old. 13 patients were on wakefulness-promoting agents/psychotropics when tested, where 8 were on serotonin–norepinephrine reuptake inhibitors/selective serotonin reuptake inhibitors. 13 patients (~45%) had a reduced mean sleep latency (MSL), where 10 minutes was used as the cut-off. All 3 MWTs were within normal limits. 5 patients (~16%) had a positive UDS. 1 patient had a low MSL and tested positive for cannabinoids and opioids. The other 4 patients with normal MSL tested positive for benzodiazepines (2), cannabinoids (1) and opioids (1). All patients were cleared for work and 85% of patients who had a low MSL returned to work during follow-up. The rate of positive UDS in patients undergoing MSLT/MWT was comparable to existing publications and re-emphasizes the relevance of mandating UDS prior to MSLT/MWT.