Liquid biopsies have become associated with the area of oncology as they hold the promise of using fragments of DNA circulating in the blood that have been shed by tumors to provide early indications of recurrence and customize treatment strategies. The same approach, though, can be used for infectious diseases. Karius has developed a liquid biopsy test to provide rapid and non-invasive detections of more than 1000 pathogens from a single blood draw. The Karius test helps clinicians avoid invasive, low-yield, and sequential diagnostic tests that can delay treatment for the most vulnerable hospitalized patients. We spoke to Alec Ford, CEO of Karius, about the company’s liquid biopsy test, how it works, and how it can change the treatment of immunocompromised patients.