All archived samples containing sufficient quantities of serum (~ 20 - 25 μL) with a diagnosis of "antigen positive" (Ag+) determined by a traditional Ag-capture assay (Trad Ag) developed by the United States Army Medical Research Institute of Infectious Diseases (USAMRIID), a recombinant Ag-capture assay for LASV NP developed by the Hemorrhagic Fever Virus Diagnostics Consortium, or from patients presenting with classical clinical symptoms of Lassa fever were used in this study. Here, RENBP is linked to Lassa fever.