Clinical comparison of Simplexa universal direct and BD GeneOhm tests for detection of toxigenic Clostridium difficile in stool samples.

We compared the performance characteristics of the Simplexa universal direct (Focus Diagnostics, Cypress, CA) and BD GeneOhm (BD Diagnostics/GeneOhm Sciences, San Diego, CA) tests for detection of toxigenic Clostridium difficile in 459 stool samples (9.4% positive). The observed agreement for the results of the two tests with 452 samples with valid test results was 98.2% (kappa, 0.9; P value of 0.73 by the McNemar test). When samples with discordant or invalid results were retested, the agreement increased to 100%.