926 - High Rates of False Negative Results in Oral Fluid Toxicology Studies Compared to Urine Toxicology Studies in Hydrocodone Drug Monitoring Programs

Friday, February 23, 2024

5:00 PM – 6:30 PM EDT

Presenting Author(s)

Saarang Singh, MD

Resident
Rutgers New Jersey Medical School - Kessler Institute for Rehabilitation
West Orange, New Jersey, United States
AS

Aakash Shah, MD

Resident Physician
NYU Emergency Medicine
New York, New York, United States

Co-Author(s)

EC

Evan Chung, MD

Resident Physician
Rutgers NJMS
West Orange, New Jersey, United States
JV

Joseph P. Valenza, MD

Director of Pain Management
Kessler Institute of Rehabilitation
West Orange, New Jersey, United States

Objectives: Urine toxicology has been used in opioid drug test monitoring for decades. Oral fluid toxicology emerged as a possible alternative during the COVID-19 pandemic for virtual supervision of remote sampling while minimizing infringements on privacy. This study aims to compare the efficacy and reliability of oral fluid and urine studies in hydrocodone drug monitoring programs.

Design: Fourteen patients taking hydrocodone for ≥10 years were randomly selected from a Chronic Pain Center. Prescription Monitoring Program (PMP) reports were reviewed for each patient. Results from oral fluid and urine samples from April to October 2021 were collected for each patient. Hydrocodone levels were measured using enzyme-linked immunoassay (ELISA) and liquid chromatography–mass spectrometry (LC/MS). A positive test result with either ELISA or LC/MS indicated their respective cutoff value was met. Test results were compared to each other to determine sensitivities of each test type.

Results: Oral fluid testing had significantly lower sensitivities for detecting hydrocodone when compared with urine toxicology studies (p< 0.001). Oral fluid testing sensitivity was 71.4% with ELISA and 85.7% with LC/MS testing. Urine testing sensitivity was 100.0%. With ELISA, 29% of subjects (4/14) in the study had false negative oral fluid toxicology results. LC/MS testing produced false negative oral fluid testing results in 14% of subjects (2/14).

Conclusions: This study suggests that oral fluid toxicology may have higher rates of false negative results compared to urine studies. In this study, oral fluid tests were 30% less sensitive than urine toxicology studies when both were performed with ELISA. Oral fluid testing with LC/MS was 15% less sensitive than urine toxicology performed with LC/MS. LC/MS could be a more reliable modality than ELISA in oral fluid testing, however it is less readily available in laboratory testing centers.