Western Equine Encephalitis Antibody, IgG and IgM

Abbrev Code:WEEP   
Order Code:LAB1060Order Name:Western Equine Encephalitis Antibody, IgG and IgM
Synonyms:LHE1215; Arbovirus Serology
Methodology:Immunofluorescence assay
CPT Codes: 86654 x2, 86654 x2
Turnaround Time:Performed Mon-Fri (May-Oct) and Mon-Wed-Fri (Nov-Apr); results are reported within 1-4 days.
Special Instructions:Lab Test Record: 1234010601

This test has been cleared, approved or is exempt by the U.S. 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.

Collection Instructions

Optimal Volume:2 mL
Minimum\Peds Volume:0.5 mL
Container:Red or gold (gel)
Alternate Containers: Red (no gel)
Causes for Rejection:Gross hemolysis or gross lipemia.

Processing and Shipping

Specimen Processing:Within 2 hours of collection, centrifuge and aliquot 1 mL, 0.15 mL minimum. Store in refrigerator.
Shipping Instructions:Ship at refrigerated temperature.
Stability:Room temperature is unacceptable; 14 days refrigerated (preferred); 14 days frozen.
Test Performed at or Referral Lab Lab Sendouts  (Mayo Medical Laboratories)


Reference Range:All ages:
IgG <1.10
IgM <1.10
  • IgG antibody is generally detectable within 1-3 weeks of onset, peaking within 1-2 months, and declining slowly thereafter.
  • IgM class antibody is reliably detected within 1-3 weeks of onset, peaking and rapidly declining within 3 months.
  • Single serum specimen IgG ≥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 U.S. it is unusual to react to more than 1 of the arboviral antigens, although Western Equine Encephalitis (WEE) and Eastern Equine Encephalitis (EEE) antigens will show some cross-reactivity; however, antibody response to the infecting virus is typically at least 8-fold higher.
  • Infections with arboviruses can occur at any age. The severity of the host response may be influenced by age; WEE tends to produce the most severe clinical infections in young persons. Infection in males is primarily due to work and sports activity.
Use:Aids in the diagnosis of Western Equine Encephalitis.

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