Rickettsia rickettsii (Rocky Mountain Spotted Fever) Antibodies, IgG & IgM by IFA
Also known as: RMSF G/M
Use
This test is used for the detection of antibodies (IgG and IgM) against Rickettsia rickettsii, the causative agent of Rocky Mountain Spotted Fever (RMSF). It is preferred for testing during the acute or convalescent phases of infection. The presence of IgG antibodies suggests current or past infection, while IgM can indicate a current or recent infection though it may persist long-term. IgM results are not routinely used due to potential false positives.
Special Instructions
Acute-phase specimens are collected during the first week of illness and convalescent-phase samples should be obtained 2-4 weeks after illness resolution. Ideally, samples should be tested simultaneously in the same facility. Submit marked convalescent samples within 25 days for paired testing.
Limitations
The CDC does not recommend IgM results for routine diagnostic testing due to potential false positives and persistence from past infections. Antibody cross-reactivity may occur with other Rickettsia species in the spotted fever group, such as R. akari, R. conorii, R. australis, and R. sibirica. Seroconversion or a fourfold increase in antibody titer is considered strong evidence of recent infection.
New York Approved
Methodology
Immunoassay (IHC)
Biomarkers
LOINC Codes
- 5307-4
- 5308-2
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.4 mL
Container
ARUP standard transport tube
Collection Instructions
Separate serum from cells as soon as possible or within 2 hours of collection. Transfer to transport tube marked as 'acute' or 'convalescent'.
Causes for Rejection
Contaminated, hemolyzed, or severely lipemic specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 2 weeks |
| Frozen | 1 year |