ARUP's Laboratory Test Directory
| 0050372: Rickettsia rickettsii (Rocky Mountain Spotted Fever) Antibody, IgM |
| Test Mnemonic: RMSF M | |
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Methodology: Indirect Immunofluorescence Assay
Performed: Mon-Fri Reported: 1-5 days |
| Specimen Required: | |
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Collect: One 4 mL SST.
Transport: 1 mL serum at 2-8°C. (Min: 0.5 mL) Submit specimen in an ARUP Standard Transport Tube. Pediatric Collection/Transport: 0.15 mL serum at 2-8°C. Remarks: Separate serum from cells ASAP. Acute and convalescent specimens must be labeled as such; parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Please mark specimen plainly as "acute" or "convalescent." Unacceptable Conditions: Severely lipemic, contaminated, or hemolyzed specimens. Stability: After separation from cells: Ambient: 2 days; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles) |
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| Reference Interval: |
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Less than 1:64: Negative - No significant level of Rickettsia rickettsii Antibody, IgM detected. 1:64 or greater: Positive - Presence of Rickettsia rickettsii Antibody, IgM detected, which may indicate a current or recent infection; however, low levels of IgM antibodies may occasionally persist for more than 12 months post-infection. |
| Interpretive Data: | |
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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.
Please refer to Statement A in the Compliance Statements section in the front of the Laboratory Test Directory. |
| CPT Code(s): | |
| 86757 |