Fig 1.

Fecal C. difficile concentrations of positive stool samples overall and detected by each test. Black circles (●) are consensus positive samples with toxigenic C. difficile detected by ≥2 tests. Upward-pointing triangles (▲) are all samples reported positive by the Xpert C. difficile/Epi test. Downward-pointing triangles (▼) are samples reported positive by the illumigene C. difficile test. Solid lines represent a 95% sensitivity cutoff for toxin detection (5.10 log₁₀ C. difficile tcdB DNA copies/ml) from reference 12. Above this line, 61/73 (83.6%) of samples were toxin positive. Below this line, 24/27 (88.9%) samples were toxin negative. Dashed lines indicate the Xpert and illumigene C. difficile DNA LOD values discussed in the text (Xpert, 3.31 log₁₀ C. difficile tcdB DNA copies/ml; illumigene, 4.52 log₁₀ C. difficile tcdB DNA copies/ml).