Test Details
Methodology
Semi-quantitative indirect fluorescent antibody (IFA)
Result Turnaround Time
4 - 5 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
The test is useful in the diagnosis of spotted fever group rickettsial infections.
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. This test is preferred for the acute or convalescent phase of disease. Acute and convalescent titers are often necessary. IgG serum endpoint titer of ≥1:64 is suggestive of infection at an unknown time and may be a sign of either past infection or early response to a recent infection. IgM titer of ≥1:64 is regarded as probable evidence of recent or ongoing infection. A four-fold or greater increase in titer between two serum samples drawn 1-2 weeks apart and tested in parallel is the best serologic indicator of a recent rickettsial infection.
Limitations
This test is preferred for the acute or convalescent phase of disease. Acute and convalescent titers are often necessary. 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.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Specimen Requirements
Specimen
Serum
Volume
0.4 mL
Minimum Volume
0.2 mL (Note: This volume does not allow for repeat testing.)
Container
Gel-barrier tube, red-top tube or serum transfer tube
Storage Instructions
Room temperature
Causes for Rejection
Hemolysis; lipemia; gross bacterial contamination
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 016502 | Spotted Fever Group Antibodies | 90260-1 | 016503 | Spotted Fever Group IgG | 22477-4 | |
| 016502 | Spotted Fever Group Antibodies | 90260-1 | 016504 | Spotted Fever Group IgM | 22479-0 | |
| 016502 | Spotted Fever Group Antibodies | 90260-1 | 016505 | Result Comment: | N/A | |
| Order Code | 016502 | |||||
| Order Code Name | Spotted Fever Group Antibodies | |||||
| Order Loinc | 90260-1 | |||||
| Result Code | 016503 | |||||
| Result Code Name | Spotted Fever Group IgG | |||||
| UofM | ||||||
| Result LOINC | 22477-4 | |||||
| Order Code | 016502 | |||||
| Order Code Name | Spotted Fever Group Antibodies | |||||
| Order Loinc | 90260-1 | |||||
| Result Code | 016504 | |||||
| Result Code Name | Spotted Fever Group IgM | |||||
| UofM | ||||||
| Result LOINC | 22479-0 | |||||
| Order Code | 016502 | |||||
| Order Code Name | Spotted Fever Group Antibodies | |||||
| Order Loinc | 90260-1 | |||||
| Result Code | 016505 | |||||
| Result Code Name | Result Comment: | |||||
| UofM | ||||||
| Result LOINC | N/A |