Clinical Utilities
West Nile virus is a flavivirus recently associated with an outbreak of encephalitis. West Nile virus IgM is usually detectable by the time symptoms appear, but IgG may not be detectable until day 4 or day 5 of illness. Antibodies induced by West Nile virus infection show extensive crossreactivity with other flaviviruses, including Denhue Fever virus and St. Louis Encephalitis virus. A positive IgM or IgG in a West Nile virus ELISA is not diagnostically conclusive of West Nile virus infection. A plaque reduction neutralization test using paired sera, and including other flaviviruses, must be performed to confirm the identity of the infecting agent.

CPT Codes

Reference Range

Component Information

Name		WEST NILE VIRUS AB IGG, SERUM
Method		ELISA
CPT Code		86789
Units
Ref Range		Negative
Reflex Reason

Name		WEST NILE VIRUS AB IGM, SERUM
Method		ELISA
CPT Code		86788
Units
Ref Range		Negative
Reflex Reason

Collection Notes

Additional Comments