The New Substance Abuse and Mental Health Services Administration Oral Fluid Cutoffs for Cocaine and Heroin-Related Analytes Applied to an Addiction Medicine Setting: Important, Unanticipated Findings with LC-MS/MS.

Abstract

We implemented oral fluid (OF) as an alternative specimen type to urine for detection of cocaine (COC) and opiate abuse in outpatient addiction medicine clinics. We implemented a 2-μg/L limit of quantification OF LC-MS/MS assay and compiled and reviewed all findings from a 22-month collection period for COC, benzoylecgonine (BZE), codeine (COD), 6-acetylmorphine (MAM), and morphine (MOR). We also compared the results of our clinical samples at different OF cutoffs and analytes specified in the new 2015 SAMHSA OF guidelines. Of 3608 OF samples, COC and BZE were positive in 593 and 508, respectively. COC or BZE was positive in 662 samples. Importantly and unexpectedly, 154 samples were COC positive and BZE negative, with 125 having COC 2.0-7.9 μg/L. A simulation with the new guideline cutoffs confirmed 65% (430 of 662) of all COC- or BZE-positive data set samples. Similarly, the new guidelines confirmed 44% (263 of 603) of data set samples positive for MOR or COD. Simulation found that the new, lower MAM guideline cutoffs detected 89% of the 382 MAM-positive samples in the data set, 104 of which the new guidelines had identified as negative for MOR and COD. COC (not BZE) is the dominant low-concentration OF analyte in an addiction medicine setting. This information will aid OF test interpretation. It also illustrates the importance of the 2015 guideline's new immunoassay cross-reactivity requirements and the likely improvement in detection of heroin use stemming from the new, lower MAM cutoffs.