Rickettsia rickettsii (Rocky Mountain Spotted Fever) Antibody, IgM
Use
This test detects IgM antibodies to Rickettsia rickettsii (Rocky Mountain Spotted Fever) during the acute phase of infection, which can be crucial for early diagnosis. Paired concurrent specimens with IgG testing can reduce false positive rates. Convalescent sera may be required for definitive diagnosis due to potential false positives or persistent IgM response from past infection.
Special Instructions
Parallel testing is preferred. Convalescent specimens must be received within 30 days from receipt of acute specimens. Mark specimens plainly as 'acute' or 'convalescent.'
Limitations
The CDC does not recommend using IgM results for routine diagnostic testing of Rocky Mountain Spotted Fever due to the potential for false positives and persistence of IgM from past infection. The response might not be specific for Rickettsia rickettsii, and reactivity should be considered as Spotted Fever group reactive, which includes other organisms such as R. akari, R. conorrii, R. australis, and R. sibirica.
New York Approved
Methodology
Immunoassay (IFT)
Biomarkers
LOINC Codes
- 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 from cells ASAP or within 2 hours of collection.
Storage Instructions
Refrigerated storage and transport.
Causes for Rejection
Contaminated, hemolyzed, or severely lipemic specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 2 weeks |
| Frozen | 1 year (avoid repeated freeze/thaw cycles) |
Other tests from different labs that may be relevant