Diagnosis of Clostridioides difficile infection (CDI) remains challenging as it involves in the first instance recognition (clinical awareness) of the patients' symptoms for clinical suspicion of CDI to warrant testing, and secondly, different laboratory tests have been described for CDI. Due to the overwhelming amount of information in the literature on CDI tests and their performance, with separately published guidelines, this review aims to provide a comprehensive but concise summary of the current state of CDI diagnostic testing. Current knowledge and the impact of using different laboratory diagnostic procedures for CDI, including the most recommended approach as a two-step algorithm and the concept of diagnostic stewardship, are being discussed. This review provides an updated overview and valuable take-home messages in the field of CDI laboratory testing and highlights that timely diagnosis is important for the clinical management of CDI and that the recommended testing procedures are increasingly becoming more widely accepted.