Ultra-sensitive C. difficile toxin assay may be critical tool for improving diagnosis of infectious disease

Findings presented at the American Society for Microbiology's ASM Microbe conference show that the ultra-sensitive Clostridium difficile toxin A/B assay in development for use on the Sgx Clarity™ system offers excellent sensitivity and may be a critical tool for improving the diagnosis of this life-threatening infection. The Sgx Clarity system is a fully-automated, in vitro diagnostics platform powered by Single Molecule Counting technology.

The Sgx Clarity system is CE marked and currently available in the European market.

In initial pilot studies, the Sgx Clarity C. difficile assay demonstrated the ability to detect the disease-causing toxins at concentrations up to 100 times lower than commercially available immunoassay methods. The turnaround time for the Sgx Clarity C. difficile toxin A/B assay was shown to be less than one hour, allowing for rapid detection and rule-out of suspected C. difficile infections (CDI).

"Having an ultra-sensitive C difficile toxin immunoassay would be a game changer," said Christopher Polage, Associate Professor of Pathology and Infectious Diseases, University of California, Davis School of Medicine. "Our experience shows the importance of toxin testing to identify patients with C difficile infection and minimize over-diagnosis but there's still a lot of anxiety in the field. Labs worry about missing individual CDI cases but hospitals are facing huge financial pressures to reduce CDI and blaming labs for using tests that don't distinguish between infected and colonized patients. Having an ultra-sensitive toxin test would allow labs to give physicians a toxin result to help maximize the accuracy of CDI diagnosis without the worry of missing cases. This would improve patient care and allow hospitals to reduce CDI rates and avoid financial penalties, representing a 'win-win' for everyone."

The Single Molecule Counting-based C. difficile toxin A and B assay aims to be the first ultra-sensitive test to offer physicians and laboratorians the specificity intrinsic to toxin tests but at a sensitivity level that rivals molecular methods. The clinical goal is to help clinicians safely to rule out C. difficile infection with greater confidence and provide clinically actionable toxin detection in under an hour.

"What makes our assays so promising is the degree of sensitivity and high precision we are able to offer with our Single Molecule Counting technology," said Dr. Jeff Bishop, Sr. Vice President of Research and Development, who is leading C. difficile assay development at Singulex. "We continue to gain important insights into its use in infectious disease through our work with key opinion leaders in the US and in Europe and are looking forward to the next stage of development."

The Singulex proprietary Single Molecule Counting technology has been validated in clinical studies involving more than 130,000 subjects, resulting in over 130 peer-reviewed publications. The company will submit data this year for regulatory clearance of the Sgx Clarity system in the United States, anticipating U.S. Food and Drug Administration clearance in 2018.