Test Catalog

Test Id : SFGP

Spotted Fever Group Antibody, IgG and IgM, Serum

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aids in the diagnosis of spotted fever group rickettsial infections

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

See Acute Tick-Borne Disease Testing Algorithm in Special Instructions.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

Immunofluorescence

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Spotted Fever Group Ab, IgG, IgM, S

Aliases
Lists additional common names for a test, as an aid in searching

Rocky Mountain Spotted Fever

RMSF

Rickettsia

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

See Acute Tick-Borne Disease Testing Algorithm in Special Instructions.

Specimen Type
Describes the specimen type validated for testing

Serum

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Container/Tube: 

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.2 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

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

Useful For
Suggests clinical disorders or settings where the test may be helpful

Aids in the diagnosis of spotted fever group rickettsial infections

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

See Acute Tick-Borne Disease Testing Algorithm in Special Instructions.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Species of Rickettsia are small (0.3-0.5 mcm x 1-2 mcm) obligately intracellular bacteria (Proteobacteria). They have a gram-negative cell wall structure. Rickettsia are found in arthropod hosts for at least part of their life cycle.

 

Rickettsial infections in the United States are caused by 2 major groups within the genus Rickettsia: spotted fever group and typhus fever group. The spotted fever group includes R rickettsii (Rocky Mountain spotted fever), R akari, R conorii (Boutonneuse fever), R australis (Queensland tick typhus), and R sibirica (North Asian tick typhus). The typhus fever group includes R typhi (murine typhus; endemic typhus) and R prowazekii (epidemic typhus).

 

R rickettsiae is the most common rickettsial species encountered in the United States and is transmitted through a tick vector (Dermacentor species or, less commonly, Rhipicephalus sanguineus). Following a 2- to 14-day incubation period, patients most commonly present with fever, chills, and myalgia. A maculopapular rash typically appears 2 to 5 days after fever onset, though approximately 10% of patients will not develop a rash. Antibodies to the spotted fever group agents are detectable within 7 to 10 days after illness onset. Demonstration of either 1) seroconversion or 2) a 4-fold change in IgG-specific antibody titers in acute and convalescent serum samples is consistent with acute or ongoing disease.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

IgG: <1:64

IgM: <1:64

Reference values apply to all ages.

Interpretation
Provides information to assist in interpretation of the test results

This test detects reactivity to the group-specific rickettsia. For example, antibody reactivity to the Rickettsia rickettsii will also react with other organisms within the spotted fever group.

 

IgG

> or =1:256:

-Serum end point titers of > or =1:256 are considered presumptive evidence of recent or current infection by organisms of appropriate rickettsial antigen group.

 

<1:256 and > or =1:64:

-Single serum end point titers > or =1:64 and <1:256 are suggestive of infection at an undetermined time and may indicate either past infection or early response to a recent rickettsial infection.

-A 4-fold or greater increase in IgG titer between 2 serum specimens drawn 1 to 2 weeks apart and tested in parallel is considered presumptive evidence of a recent or current infection.

-In patients infected with organisms within the rickettsial groups, IgG antibody is generally detectable within 1 to 2 weeks of onset of symptoms, peaking within 1 to 2 months and declining thereafter. Following prompt antimicrobial treatment, titers generally decline below detectable levels within 8 to 11 months. With relapse, prior immunization, or delayed antibiotic treatment, IgG levels may remain elevated for more than a year postonset.

 

IgM

> or =1:64:

-Titers of > or =1:64 are considered presumptive evidence of recent or current infection by organisms of appropriate rickettsial antigen group.

 

<1:64:

-Titers <1:64 suggest that the patient does not have an acute rickettsial infection.

-IgM class antibody is transiently detected within 1 to 2 weeks of onset of symptoms, usually declining rapidly within 3 months following prompt antibiotic treatment. These levels will also be elevated for an extended period with relapse, prior immunization, or delayed antibiotic treatment.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

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 drawn 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.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Walker DH, Bouyer DH: Rickettsia: In Manual of Clinical Microbiology. Eighth edition. Edited by PR Murray, EJ Baron, JH Jorgenson et al. Washington, DC, ASM Press, 2003, pp 1005-1014

2. Helmick C, Bernard K, D'Angelo L: Rocky Mountain spotted fever. Clinical laboratory and epidemiological features of 262 cases. J Clin Microbiol 1984;12:343-350

3. Centers for Disease Control and Prevention: Tickborne diseases of the United States. A Reference Manual for HealthCare Providers. First Edition 2013. Available at www.cdc.gov/lyme/resources/TickborneDiseases.pdf

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

Substrate slides containing antigen wells for measuring antibodies to both groups of Rickettsia (spotted fever and typhus) are obtained from Focus Technologies Inc. The indirect immunofluorescence assay (IFA) is a 2-stage "sandwich" procedure. In the first stage, the patient serum is diluted in yolk sac diluent. The diluted serum is placed on the slide in contact with the substrate and incubated. Following incubation, the slide is washed in buffered saline, which removes unbound serum antibodies. In the second stage, each antigen well is overlaid with fluorescein-labeled antibody to human IgG or IgM. The slide is incubated allowing antigen-antibody complexes to react with the fluorescein-labeled antihuman IgG or IgM. After the slide is washed, dried, and mounted, it is examined using fluorescence microscopy. Positive reactions appear as rickettsial bodies exhibiting bright apple-green cytoplasmic fluorescence against a background of orange to red yolk sac matrix. Semiquantitative end point titers are obtained by testing serial dilutions of positive specimens.(Package insert: Rickettsia IFA IgM, Focus Technologies Inc, Cypress, CA, August 12, 2016)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Same day/1 to 3 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

14 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

86757 x 2

LOINC® 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
Result LOINC Value Tooltip
84342 Spotted Fever Group Ab, IgG, S 5313-2
84346 Spotted Fever Group Ab, IgM, S 5315-7

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports