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.

Semi-Quantitative Indirect Fluorescent Antibody
Tue, Fri
1-5 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Serum separator tube. 
Specimen Preparation
Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.1 mL) Parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute specimens. Mark specimens plainly as acute or convalescent. 
Storage/Transport Temperature
Unacceptable Conditions
Contaminated, hemolyzed, or severely lipemic, specimens. 
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles) 
Reference Interval
< 1:64  Negative - No significant level of Rickettsia typhi IgM antibody detected.
≥1:64  Positive - Presence of IgM antibody to Rickettsia typhi detected, suggestive of recent infection.
Interpretive Data
This test is for antibodies to Rickettsia typhi. Any antibody reactivity to Rickettsia typhi antigen should, however, also be considered group-reactive for the Typhus Fever group (Rickettsia prowazekii). Seroconversions or an increase between acute and convalescent IgG and IgM titers of at least fourfold is considered strong evidence of recent infection.

While the presence of IgM antibodies suggests recent infection, low levels of IgM antibodies may occasionally persist for more than 12 months post-infection.

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.
  • R typhi IgM antibody
  • Typhus Fever Group IgM Antibody