Diagnosis of West Nile virus infections: Evaluation of different laboratory methods

Table 2 Laboratory tests used for the diagnosis of West Nile virus infection

Method	Manufacturer/Protocol	Reference values
RT-PCR	FP: AAG TTG AGT AGA CGG TGC TG; RP: AGA CGG TTC TGA GGG CTT AC; Probe: FAM-CAA CCC CAG GAG GAC TGG-TAMRA
IgM ELISA	Euroimmun, Lübeck, Germany	Ratio < 0.8 negative; 0.8-1.1 borderline; > 0.1 positive
IgG ELISA	Euroimmun, Lübeck, Germany	RU/mL < 16 negative, 16-22 borderline; > 22 positive
IgG avidity	Euroimmun, Lübeck, Germany	AI < 40% low; 40%-60% borderline; > 60% high
VNT	In house	Titer ≥ 10 positive

AI: Avidity index; ELISA: enzyme immunoassay; IgG: Immunoglobulin G; IgM: Immunoglobulin M; RT-PCR: Reverse transcription-polymerase chain reaction; RU: Relative units; VNT: Virus neutralization test.