1 Department of Medicine, Duke University School of Medicine, Durham, NC, USA; Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA; Department of Medicine, Durham Veterans Affairs Medical Center, Durham, NC, USA. Electronic address: julia.scialla@duke.edu.
2 Litholink Corp, Laboratory Corporation of America Holdings, Chicago, IL, USA.
3 Department of Medicine, Duke University School of Medicine, Durham, NC, USA.