A-328 Urine Toxicology Screening: Tetrahydrocannabinol Positivity Patterns at an U.S. Urban Tertiary Care Children's Hospital

Abstract Background Given the recent legalization of recreational and medical marijuana in different states, there is an increasing exposure of children and teenagers to marijuana products which has led to an increase in health care visits and hospitalizations. Our drug testing algorithm uses an immunoassay test for initial urinary drug screening (UDS) followed by an automatic confirmatory test only when a positive UDS result is obtained. The immunoassay test is performed in-house and detects the major metabolites of delta9- tetrahydrocannabinol (THC), the main psychoactive component of marijuana. In contrast, the liquid chromatography-tandem mass spectrometry (LC-MS/MS) confirmatory test is more specific towards THC and is carried out in an external lab. In light of the ongoing trend of marijuana exposure cases and the fact that immunoassay cross-reactivity with non-cannabinoid compounds is uncommon, we aim to assess the necessity of automatic confirmatory tests in our patient population and evaluate its impact on patient management. Methods We conducted a retrospective study to assess the trends in cannabinoid hospital-related encounters by age, gender, and incidence with other drugs, in our population among the main campus and satellites (November 2021–October 2022). The UDS tests that were positive for cannabinoids were further evaluated to assess their agreement with the confirmatory testing. Results Cannabinoid positive tests account for 62.0% (504/813) of all positive UDS tests in all our locations and 84% (425/504) of the cases did not test positive for other drug classes. Among this population, 92.7% (467/504) are in the adolescent age (≥13 years), whereas 7.3% (37/504) were children (<13 years). Female population comprises 56.0% (217/504) of the cases whereas male, 43% (271/504) of the cases. The true positive rate for the immunoassay test was 99.6% (465/467) and 94.6% (35/37) for adolescents and children, respectively. Clinical decisions were made after a positive immunoassay result and before the confirmatory test as this is a send out test and takes a few days to receive the result. Conclusion Our evidence-based approach demonstrates unnecessary confirmatory testing for the adolescent group in our population due to a high positivity rate (99.6%). Discontinuing automatic confirmatory testing for this group will eliminate workload and reduce healthcare costs. On the other hand, automatic confirmatory testing in children will continue as these exposures are mainly considered unintentional and require more investigation.