Karius Test accurately detects invasive fungal infections, shows study

Jul 20 2018

Karius, a life sciences company transforming infectious disease diagnostics with genomics and data through the innovative use of next-generation sequencing to analyze microbial cell-free DNA, announced today the positive results of a clinical study using blood samples from patients with confirmed invasive fungal infections (IFI). The study showed that the Karius^® Test, a noninvasive blood test, was able to detect both Aspergillus and non-Aspergillus molds in patients with proven IFI, who were previously diagnosed by invasive samplings of infected tissue. The results were published in Diagnostic Microbiology and Infectious Disease, a peer-reviewed journal in clinical microbiology focused on the diagnosis and treatment of infectious disease.

Despite the availability of a number of new antifungal therapies, invasive fungal infections remain a major cause of morbidity and mortality, especially in immunocompromised patients. Although physicians traditionally rely on tissue biopsies for life-threatening deep-seated infections to provide a microbiologic diagnosis, an invasive procedure might not be an option in certain cases and these procedures could lead to high morbidity and contribute to additional healthcare costs.

“There is a significant need for a non-invasive blood test that can aid in the diagnosis of deep infections, particularly when an invasive diagnostic procedure is not possible, or in immunocompromised patients where the number of potential pathogens is very large,” said David K. Hong, M.D., VP Medical Affairs and Clinical Development at Karius, and lead author of the study. Liquid biopsies have proven to be effective in oncology, and the technology is poised to have wider applications, particularly in infectious disease.

The Karius Test is a novel next-generation sequencing assay that was used to detect pathogen-derived cell-free DNA in patients with IFI. The study included nine adult patients at Stanford University Medical Center with diagnosed IFI, as confirmed by standard tissue biopsies. Patients had deep fungal infections in their lungs, heart, brain, sternum, small bowel or peri-pancreatic lymph nodes. Plasma samples were collected from these patients and the samples were sent to Karius’ laboratory in Redwood City, California for analysis.

In the study, the Karius Test showed concordance with standard, more invasive diagnostic methods. The Karius Test accurately identified pathogens at the species level. In one patient, Aspergillus lentulus was identified while conventional culture diagnosis found Aspergillus fumigatus species complex. This is a key finding because A.lentulus is resistant to first-line antifungal medications and identifying the right pathogen can lead to more effective antifungal therapy.