Caulfield AJ, et al. - In this study, they examined the performance of 4 nucleic acid amplification test (NAAT) assays as part of a 2-step algorithm that involves reflexive NAAT following enzyme immunoassay (EIA) testing that was indeterminate for glutamate dehydrogenase (GDH) antigen and toxin A/B (GDH⁺/toxin^- or GDH^-/toxin⁺) for the detection of Clostridium difficile in stool specimens. Findings revealed that the GDH portion of the EIA test had comparable sensitivity to the NAAT assays.