Method comparison of the Ortho Vitros Fusion 5,1 chemistry analyzer and the Roche COBAS Integra 400 for urine drug screen testing in the emergency department.

Exposure to drugs and toxins is a major cause for the rising number of emergency department visits each year. Immunoassays are commonly used in the emergency department to provide rapid turnaround time for acute care. The purpose of this study was to compare two automated immunoassay chemistry analyzers to determine which platform produced the fewest number of false positive/negative results. Residual patient urine samples were were collected for each of the following drugs/drug classes: cocaine (n 5 40), opiates (n 5 45), and amphetamines (n 5 54) and confirmed either positive or negative by mass spectrometry. Split sample analyses of these specimens were performed on both the Roche COBAS INTEGRA 400 plus and Ortho Vitros 5,1 FS instruments. The results from the two chemistry analyzers were compared to confirmed results. Both immunoassays were prone to false positive results for cocaine and false negative results for opiates and amphetamines. The Vitros Fusion analyzer generated fewer false positive and false negative results for opiate and amphetamine testing than the Roche Integra, but the platforms performed comparably for cocaine.