Rickettsia typhi (Typhus Fever) Antibody, IgM by IFA
Ordering Recommendation
Confirm presence of Rickettsia typhi. Panel test (IgG and IgM) is preferred. Requires comparison of acute- to convalescent-phase serology.
New York DOH Approval Status
Specimen Required
Serum Separator Tube (SST).
Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP standard transport tube. (Min: 0.4 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens.
Refrigerated.
Contaminated, hemolyzed, or severely lipemic, specimens.
Mark specimens plainly as "acute" or "convalescent."
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
Methodology
Semi-Quantitative Indirect Fluorescent Antibody (IFA)
Performed
Sun-Sat
Reported
1-3 days
Reference Interval
Test Number |
Components |
Reference Interval |
---|---|---|
Typhus Fever Antibody, IgM | Less than 1:64 |
Interpretive Data
Antibody reactivity to Rickettsia typhi antigen should be considered group-reactive for the Typhus Fever group, which includes Rickettsia prowazekii.
Seroconversion between acute and convalescent sera is considered strong evidence of recent infection. The best evidence for infection is a significant change (fourfold difference in titer) on two appropriately timed specimens, where both tests are done in the same laboratory at the same time. Acute-phase specimens are collected during the first week of illness and convalescent-phase samples are generally obtained 2-4 weeks after resolution of illness. Ideally these samples should be tested simultaneously at the same facility. If the sample submitted was collected during the acute-phase of illness, submit a marked convalescent sample within 25 days for paired testing.
Component |
Unit Of Measure |
Interpretation |
---|---|---|
Typhus Fever Antibody, IgM | Less than 1:64 1:64 or greater |
Negative - No significant level of IgM antibody detected. Positive - Presence of IgM antibody to 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. |
FDA
Note
Hotline History
Hotline History
CPT Codes
86757
Components
Component Test Code* | Component Chart Name | LOINC |
---|---|---|
0050383 | Typhus Fever Antibody, IgM | 5325-6 |
Aliases
- R typhi IgM antibody
- Typhus Fever Group IgM Antibody