GDH/toxin EIA-based assays also have Temsirolimus nmr shorter turnaround times and test costs are lower when compared to PCR. However, GDH and toxin EIAs have repeatedly been reported

to have a lower sensitivity compared to PCR and CCNA [11, 15, 28–30] despite being widely used and recommended as a two-step algorithm [13, 14]. Our clinical study found that, when compared to clinical diagnosis, 16.2% of true CDIs were GDH negative and a further 59.7% of GDH positive, clinically confirmed CDIs were negative in toxin EIA [17]. This is in line with Guerrero et al. [31] and Stahlmann et al. [32] who reported that a third of CDI-positive patients would have been missed using toxin EIA compared to PCR. This is important, as patients with EIA-negative results did not differ in clinical presentation from EIA-positive patients and posed a significant risk for transmission [29]. Considering that around 25% of CDI patients were suggested Nutlin-3a Crenolanib in vitro to be infected by ward-based patient-to-patient transmission [33, 34], the clinical and financial impact of misidentification of CDI cases would be important. In laboratories using a two-step GDH/toxin EIA algorithm, costs incurred due to repeat testing performed when

the GDH result alone is positive, increased use of antibiotics for those patients with GDH positives which do not confirm with EIA and the increased length of time to a positive toxin result have to be considered. In our clinical study, 35.2% of patients with GDH-positive specimens did not clinically present CDI [17]. Retesting, treating and isolating patients with false-positive results wastes resources. We observed that GDH failed to pick up a case of CDI, part of a ward outbreak, learn more which was presumptive C. difficile ribotype 027 positive with PCR and two GDH-positive 027 cases tested negative by toxin EIA. The diagnostic accuracy of PCR methods has been established in several trials [11, 15, 28, 29, 35]. However,

additional positives identified by PCR are often described as false positives when results are only compared to other assays in the laboratory setting and clinical presentation is not considered [36]. Our clinical study showed that out of 59 discrepant samples (CCNA negative but PCR positive), 54 (91.5%) were found to be true positives on clinical diagnosis which demonstrates convincingly that PCR results are reliable and accurate for diagnosing CDI, at the same time reducing the need for repeat testing. This was confirmed by Napierala et al. [37] who found that after implementation of PCR, testing volume as well as CDI rates decreased significantly. Increased faith of clinicians in a more accurate testing method not only impacts on CDI-positive patients but also affects CDI-negative patients, who can be assessed for other gastrointestinal problems at an earlier point in time without having to revisit CDI as a cause for diarrhea. Other patients can be discharged without further C.