An evaluation study of Syva Emit II reagents using the Chem 1 was performed for the following drugs: barbiturates, benzodiazepines, cannabinoids, benzoylecgonine, opiates, and phencyclidine. The Emit II reagents (100-mL bottles) were reconstituted to 70 mL and evaluated against the Emit d.a.u. reagents. A minimum of 446 samples were run for each drug. For all drugs tested, there were a total of 11 discordant results between the two reagents. The Emit II reagent was found to be correct on 8 of the 11 discordances after retesting by FPIA or GC/MS. The CV of within-run and day-to-day precision of the Emit II was 1.8% or less and 12.3% or less, respectively.