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Rickettsia typhi (Typhus Fever) Antibody, IgM by IFA
0050383
Ordering Recommendation

Confirm presence of Rickettsia typhi. Panel test (IgG and IgM) is preferred. Requires comparison of acute- to convalescent-phase serology.

Mnemonic
TYPHU M
Methodology
Semi-Quantitative Indirect Fluorescent Antibody
Performed
Sun-Sat
Reported
1-3 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
 
Collect
Serum Separator Tube (SST). 
Specimen Preparation
Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.3 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. 
Storage/Transport Temperature
Refrigerated. 
Unacceptable Conditions
Contaminated, hemolyzed, or severely lipemic, specimens. 
Remarks
Mark specimens plainly as "acute" or "convalescent." 
Stability
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles) 
Reference Interval
Less than 1:64Negative - No significant level of IgM antibody detected.
1:64 or greaterPositive - 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.

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.

Note
Hotline History
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Components
Component Test Code*Component Chart NameLOINC
0050383Typhus Fever Antibody, IgM5325-6
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • R typhi IgM antibody
  • Typhus Fever Group IgM Antibody