A collection of reagents and other associated materials intended to be used for the qualitative and/or quantitative detection of immunoglobulin G (IgG) antibodies to one or multiple species of the rickettsial bacteria associated with spotted fever in a clinical specimen, using an enzyme immunoassay (EIA) method. Rickettsia species intended to be detected may include Rickettsia rickettsii, R. akari, R. conorii, R. sibirica, R. australis, R. japonica, R. africae, R. honei and/or R. felis.