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Test Code LAB1264 Spotted Fever Group Antibody, IgG and IgM, Serum

Reporting Name

Spotted Fever Group Ab, IgG, IgM, S

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.2 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 14 days
  Frozen  14 days

Reference Values

IgG: <1:64

IgM: <1:64

Reference values apply to all ages.

Day(s) Performed

Monday through Friday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

86757 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SFGP Spotted Fever Group Ab, IgG, IgM, S 90260-1

 

Result ID Test Result Name Result LOINC Value
84342 Spotted Fever Group Ab, IgG, S In Process
84346 Spotted Fever Group Ab, IgM, S In Process

Testing Algorithm

For more information see Acute Tick-Borne Disease Testing Algorithm.

Useful For

Aiding in the diagnosis of spotted fever group rickettsial infections

Cautions

Cross-reactivity within the spotted fever group precludes the speciation of the infecting rickettsia by this procedure. Sera reactive with Rickettsia rickettsii must be termed "spotted fever group-positive." Spotted fever and typhus fever intragroup cross-reactivity is weak: cross-reactive titers are typically at least 16-fold lower than group-specific titers.

 

Antibody is variably absent for 1 to 2 weeks after onset of symptoms and an initial negative titer should not be used to exclude the diagnosis of rickettsial disease. A second serum specimen should be collected 1 to 2 weeks later to establish the diagnosis in such patients.

 

IgM titers must be interpreted with caution, especially in the absence of IgG. Cases should be further evaluated clinically or serologically by testing acute and convalescent serum in parallel to demonstrate a 4-fold or greater change in IgG or IgM titer.

 

Diagnosis of recent infection based on a single elevated IgG titer is complicated by the slow decline of antibody titer from past infection in many individuals. Titers may remain elevated for longer than 12 months, especially where antibiotic treatment was delayed or prior immunization was involved.

 

Some patients may maintain a long-term IgM titer, with or without IgG. It is important to check the IgM titer 1 to 2 weeks following testing of an acute specimen.

Report Available

Same day/1 to 3 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject

NY State Approved

Yes

Method Name

Immunofluorescence

Forms

If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.