False-Positive Urine Screening for Benzodiazepines: An Association with Sertraline?: A Two-year Retrospective Chart Analysis.

OBJECTIVE: To determine the frequency of false-positive benzodiazepine screens associated with sertraline use at the authors' institution.

METHOD: Urine drug screen results spanning a two-year period were data mined to identify those positive for benzodiazepines. When confirmatory gas chromatography-mass spectrometry determined false positives, they were subsequently cross-referenced against pharmacy records to identify patients with active prescriptions for sertraline at the time of the initial urinary drug screen.

RESULTS: Of the 522 records reviewed, 160 were later determined to be false positives by confirmatory gas chromatography-mass spectrometry. Sixty-two of those were associated with a concomitant benzodiazepine prescription. Of the 98 remaining, 26 were associated with a concomitant sertraline prescription.

CONCLUSION: Our findings suggest that sertraline may be an unreported cause of false-positive benzodiazepine results in a widely used screening assay.