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Test Code TFAGM Rickettsia typhi (Typhus Fever) Antibodies, IgG & IgM by IFA

Clinical Indications

Confirm presence of Rickettsia typhi. Requires comparison of acute- to convalescent-phase serology.

Additional Test Codes

Epic Order Name: TYPHUS FEVER AB IGG&IGM (aka TFAGM)
Sunquest Order Code: TFAGM
Epic Px Code: LAB2716

Specimen Collection Type

Preferred: Gold
Acceptable: Red

Minimum Collection Volume

0.3 mL

Reference Range

Components

Reference Interval

Rickettsia typhi (Typhus Fever) Antibody, IgG by IFA

Less than 1:64

Negative - No significant level of IgG antibody detected.

1:64-1:128

Equivocal - Questionable presence of IgG antibody detected.  Repeat testing in 10-14 days may be helpful.

1:256 or greater

Positive - Presence of IgG antibody detected, suggestive of current or past infection.

Rickettsia typhi (Typhus Fever) Antibody, IgM by IFA

Less than 1:64

Negative - No significant level of IgM antibody detected.

1:64 or greater

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.

Critical Value

N/A

Interpretation

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.

Rejection Criteria

Contaminated, hemolyzed, or severely lipemic specimens.

Specimen Availability for Add-on Testing

2 Days

Specimen Stability

Refrigerated (preferred): 2 weeks
Ambient: 48 hours
Frozen: 1 year

Day(s) Performed

Sun-Sat

Performing Lab- Department

TUKHS-BH-Mail Outs

CPT Code

86757 × 2

LOINC Code

Typhus Fever Antibody, IgG: 5324-9
Typhus Fever Antibody, IgM: 5325-6

Test Alias

Murine Typhus Antibodies
R. typhi antibodies
Typhus Fever Group Antibody, IgG and IgM, Serum

Additional Information / Notes

N/A