FIG 1.

Flowchart of included samples. (Top) LUMC cohort. (Bottom) Amphia Hospital cohort. *, No culture was performed because a culture with positive results had been performed within the previous week. **, No culture was performed because a culture with positive results had been performed within the previous week (n = 1) or because positive TcdB results were obtained retrospectively during the implementation phase of the tcdB NAAT, when samples were routinely tested by toxin (Tox) A/B EIA only.