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Test Code MISC2MAYOEEEP Eastern Equine Encephalitis Antibody, IgG and IgM, Serum

Useful For

Aiding in the diagnosis of Eastern equine encephalitis

Method Name

Immunofluorescence Assay (IFA)

Reporting Name

East Equine Enceph Ab, IgG and IgM, S

Specimen Type

Serum


Specimen Required


Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Specimen Minimum Volume

0.15 mL

Specimen Stability Information

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

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject

Clinical Information

Eastern equine encephalitis (EEE) is within the alphavirus group. It is a low prevalence cause of human disease in the Eastern and Gulf Coast states. EEE is maintained by a cycle of mosquito/wild bird transmission, peaking in the summer and early fall, when man may become an adventitious host. The most common clinically apparent manifestation is a mild undifferentiated febrile illness, usually with headache.

 

Central nervous system involvement is demonstrated in only a minority of infected individuals; it is more abrupt and more severe with EEE than other arboviruses, with children being more susceptible to severe disease. Fatality rates are approximately 70% for EEE.

Reference Values

IgG: <1:10

IgM: <1:10

Reference values apply to all ages.

Interpretation

In patients infected with this virus, IgG antibody is generally detectable within 1 to 3 weeks of onset, peaking within 1 to 2 months, and declining slowly thereafter.

 

IgM class antibody is also reliably detected within 1 to 3 weeks of onset, peaking and rapidly declining within 3 months.

 

Single serum specimen IgG greater than or equal to 1:10 indicates exposure to the virus.

 

Results from a single serum specimen can differentiate early (acute) infection from past infection with immunity if IgM is positive (suggests acute infection).

 

A 4-fold or greater rise in IgG antibody titer in acute and convalescent sera indicate recent infection.

 

In the United States it is unusual for any patient to show positive reactions to more than 1 of the arboviral antigens, although Western equine encephalitis and Eastern equine encephalitis antigens will show a noticeable cross-reactivity.

 

Infections can occur at any age. The age distribution depends on the degree of exposure to the particular transmitting arthropod relating to age and sex, as well as the occupational, vocational, and recreational habits of the individuals. Once humans have been infected, the severity of the host response may be influenced by age.

Method Description

Dilutions of test sera are prepared and allowed to react with substrate cells infected with Eastern equine encephalitis virus. If IgG antibodies to this virus are present in the serum of the patient, an antigen-antibody complex will develop that can be detected by a fluorescein-labeled antibody directed to human globulin.(Tsai TF: Arboviruses. In: Murray PR, Baron EJ, Pfaller MA, et al, eds. Manual of Clinical Microbiology. 7th ed. ASM Press, 1999; 1107-1124; Beaty BJ, Casals J, Brown KL, et al: Indirect fluorescent-antibody technique for serological diagnosis of LaCrosse [California] virus infections. J Clin Microbiol. 1982;15:429-434; Beckham JD, Tyler KL: Arbovirus Infections. Continuum (Minneap Minn). 2015 Dec;21(6 Neuroinfectious Disease):1599-1611. doi: 10.1212/CON.0000000000000240)

Day(s) Performed

May through October: Monday through Friday

November through April: Monday, Wednesday, Friday

Report Available

Same day/1 to 4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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

86652 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
EEEP East Equine Enceph Ab, IgG and IgM, S 69034-7

 

Result ID Test Result Name Result LOINC Value
83354 East Equine Enceph Ab, IgG, S 10896-9
83355 East Equine Enceph Ab, IgM, S 10898-5

Secondary ID

83155

Forms

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

Testing Algorithm

See Mosquito-borne Disease Laboratory Testing in Special Instructions.