Rocky Mountain spotted fever (RMSF) is a tick-borne disease caused by the intracellular bacterium Rickettsia rickettsii.
Antibody reactivity to Rickettsia rickettsii antigen should be considered Spotted Fever group reactive. Other organisms within the group include R. akari, R. conorrii, R. australis, and R. sibirica.
The standard serologic test for diagnosis of RMSF is the indirect immunofluorescence antibody (IFA) assay for immunoglobulin G (IgG) using R. rickettsii antigen.
R. rickettsii is closely related to other pathogenic spotted fever group Rickettsia (SFGR) species, including R. akari, R. parkeri, and Rickettsia 364D. Closely related species of SFGR share similar antigens such that antibodies directed to one of these antigens can cross-react with other heterologous spotted fever group antigens.
Early recognition and treatment with doxycycline is critical to survival.
Rocky Mountain spotted fever (RMSF) can be difficult to diagnose due to the non-specific signs and symptoms in early stages of illness. Signs and symptoms can vary from patient to patient and can resemble other, more common diseases. Nonetheless, early consideration of rickettsial disease in the differential diagnosis and empiric treatment is crucial to prevent severe illness and death.
Testing for RMSF should be considered for any person with a compatible illness and known risk factors, such as those who remember a tick bite or have been exposed to areas with ticks.
Signs & Symptoms:
Early illness (days 1-4)
Late illness (day 5 or later)
Risk factors for severe illness
The CDC does not use IgM results for routine diagnostic testing of Rocky Mountain Spotted Fever, as the response may not be specific for the agent (resulting in false positives) and the IgM response may be persistent from past infection.
ABS; Aby; Antby; Anti; Antibodies; Antibody; Arbitrary concentration; Autoantibodies; Autoantibody; Immune globulin G; Immunoglobulin G; Microbiology; Point in time; QNT; Quan; Quant; Quantitative; R rickettsi; R rickettsii; Random; Ricket; Rickettsial; RMSF; Rocky mountain spotted fever; Serum; Spotted fever; SR
$79 per year
$6.60 per month billed annually
$79 per year
Save time on interpreting lab results with the largest database of biomarkers online. In-depth research on any test at your fingertips, all stored and tracked in one place.Learn More