Arbovirus IgM EIA, St. Louis Encephalitis and West Nile

Laboratory Fee Schedule

Procedure: MZZ0085A

CPT: 86653, 86789


Synonym(s): Flavivirus, Arbovirus IgM, SLEV IgM, WNV IgM 
Requisition Form G-2A.
Test Description Capture Enzyme Immunoassay for the detection of IgM Antibodies to West Nile and St. Louis Encephalitis Viruses.
Pre-Approval Needed N/A
Supplemental Information Required N/A
Supplemental Form(s) N/A
Performed on Specimens from (sources) Human
Sample/Specimen Type for Testing
  • Serum 1.0 ml
  • Cerebral Spinal Fluid (CSF) 400 uL
Minimum Volume/Size Required
  • Serum 1.0 mL
  • Cerebral Spinal Fluid (CSF) 400 µL 
Storage/Preservation Prior to Shipping
  • Store specimens at 2°C to 8°C for up to 48 hours.
  • For storage longer than 48 hours, store at -20°C or below. 
Transport Medium N/A
Specimen Labeling
  • Two patient-specific identifiers required on specimen (e.g., patient full name, date of birth, medical record number).
  • Three patient identifiers are preferred.
  • Patient identifiers on specimen label must exactly match identifiers on submission form (e.g., abbreviated name on label and full name on form is not acceptable.) 
  • Additional DSHS Laboratory specimen labeling guidelines available online here
Shipping and Specimen Handling Requirements
  • Ship according to Dangerous Goods Regulations, IATA, and/or CFR 49.
  • Category B Biological Substance, UN3373 shipping requirements apply. 
  • Handle as infectious agent using universal precautions. 
  • Triple' contain in accordance with federal shipping regulations for infectious agents. 
  • Submitters are responsible for packaging and shipping specimens according to regulatory requirements. 
  • Additional DSHS Laboratory specimen shipping guidelines online here. 
  • If specimens will arrive at the Lab within 48 hours of collection, refrigerate at 2°C –8°C and ship overnight on cold packs.
  • If specimens will arrive at the Lab more than 48 hours after time of collection, freeze at -20°C or colder, and ship overnight on dry ice.
Method IgM Antibody Capture Enzyme-Linked Immunosorbent Assay (MAC-ELISA).
Turn-around Time 8 working days.
  • Reliable results are dependent on adequate specimen collection. 
  • Cross-reactions can occur between flaviviruses. 
  • Specific IgG can compete with IgM and may result in a false negative. 
  • Rheumatoid factor in presence of specific IgG may result in a false positive. 
Common Causes for Rejection
  • Insufficient quantity
  • Unacceptable specimen type or source
  • Improper shipping conditions
  • Expired media or collection container
  • Expired reagents/media/collection container. 
  • Discrepancies between G-2V submission form and specimen label. 
  • Missing/incomplete/illegible submission form or label.
Additional Information
  • Results serve only as an aid in diagnosis and should be interpreted in relation to patient travel history, clinical symptoms, other diagnostic findings, and epidemiological data.
  • The absence of detectable IgM antibody does not rule out the possibility of recent or current infection.
  • Convalescent serum specimen should be tested if an early acute CSF or serum is negative. 
  • For most, IgM is detectable 8 days post-onset of symptoms and can persist for at least 45 days and sometimes for up to 90 days. 
  • Reactive samples will be forwarded to CDC for confirmatory testing by Plaque Reduction Neutralization Test (PRNT).
  • Minimum volume for CDC confirmation testing is 0.5 mL.