False-Positive Results in Urine Drug Screening in Healthy Volunteers Participating in Phase 1 Studies With Efavirenz and Rifampin la Porte, Charles J. L.; Droste, Jacqueline A. H.; Burger, David M. la Porte, Charles J. L.; Droste, Jacqueline A. H.; Burger, David M. Less Therapeutic Drug Monitoring. 28(2):286, April 2006. Favorite PDF Permissions Buy