Determination of the performance of a novel diagnostic test for <i>Clostridioides difficile</i> toxins A and B using latent class analysis

<i>Clostridioides difficile</i> infection (CDI) is the most important infectious cause of hospital-associated diarrhea worldwide, but its diagnosis remains challenging. Nucleic acid amplification tests (NAATs) targeting the <i>C. difficile</i> (CD) toxin B gene have suboptimal specificity due to the presence of CD asymptomatic colonization, while enzyme immunoassays (EIAs) that detect the toxin itself are much more specific but are limited by low sensitivity. New assays for detecting CD toxins were developed using single-molecule array (SIMOA) technology, which have much lower limits of toxin detection than conventional EIAs, potentially improving the sensitivity of these conventional EIAs while remaining highly specific. In this study, we use latent class analysis to evaluate the sensitivity and specificity of different diagnostic tests for CD, including the novel SIMOA toxin assays, in detecting the different CD targets: the presence of CD bacterium, the presence of CD toxin gene, and the presence of CD toxin.