Table 1.
Overall results of the EQA for the serological detection of WN virus infection
| Sample N° | ||||||||||||
| Lab. N° | Assay used | #8 anti-WN | #12 anti-WN | #5 anti-WN | #6 anti-WN | #10 anti-TBE | #7 anti-YF | #11 anti-DEN | #3 neg. | #2 neg. | #1 unspec. | Correct results in % |
| 2‡ | EIA/IFAih | (-)/+ | (-)/+ | (-)/+ | -/+ | - | - | - | - | - | - | 100.0 |
| 4 | EIAih | +/+ | +/+ | +/+ | -/+ | -* | -* | - | - | - | - | 100.0 |
| 8 | EIAih | +/(-) | +/+ | +/+ | -/+ | - | -/e | - | - | - | - | 100.0 |
| 18 | EIAih | +/+ | +/+ | +/+ | -/+ | - | -* | - | - | - | - | 100.0 |
| 29 | IFAih | (-)/+ | (-)/+ | +/+ | -/+ | - | -* | - | - | - | - | 100.0 |
| 37 | EIAih | + | + | + | + | - | -* | - | - | - | - | 100.0 |
| 5 | EIAF | +/+ | e/+ | +/+ | -/+ | - | -/(+) | - | - | - | - | 90.0 |
| 6 | IFAih | (-)/+ | (-)/+ | +/+ | -/+ | - | -/(+) | - | - | - | - | 90.0 |
| 9 | IFAP | (-) | (+)/(+) | +/+ | -/(+) | - | -* | - | - | - | - | 90.0 |
| 10 | IFAih | (-)/+ | (-) | (-)/+ | -/+ | - | - | - | - | - | - | 90.0 |
| 14 | EIAih | (-)/+ | +/+ | (-)/+ | -/+ | - | -/(+) | - | - | - | - | 90.0 |
| 16 | EIAF | +/+ | e/+ | +/+ | -/+ | - | -/(+) | - | - | - | - | 90.0 |
| 17 | IFAih | (-)/+ | (-)/+ | +/+ | -/+ | - | -/e | - | - | - | -/(+) | 90.0 |
| 20 | EIAF | +/+ | e/+ | +/+ | -/+ | - | -/(+) | - | - | - | - | 90.0 |
| 23 | EIAF | (-)/+ | (-)/+ | (-)/+ | -/+ | - | -/(+) | - | - | - | - | 90.0 |
| 35 | EIAF+P | e/+ | e/+ | e/+ | -/+ | - | -/(+) | - | - | - | - | 90.0 |
| 11 | IFAih | +/+ | +/+ | +/+ | (+)/+ | - | -/(+) | - | - | - | (+) | 80.0 |
| 13 | EIAF | +/+ | e/+ | e/+ | -/+ | - | -/(+) | (+)/- | - | - | - | 80.0 |
| 24 | EIAih | + | (-) | + | (-) | - | - | - | - | - | - | 80.0 |
| 25 | EIAF | (+)/+ | (-)/e | (+)/+ | -/+ | - | -/(+) | - | - | - | - | 80.0 |
| 33 | EIAih | + | + | + | + | (+) | (+) | - | - | - | - | 80.0 |
| 15 | EIAF | +/+ | +/+ | +/+ | -/+ | (+)/- | -/(+) | ind. | - | - | - | 77.8 |
| 30 | EIAih | (-) | (-) | + | + | - | (+) | - | - | - | - | 70.0 |
| 7 | NTih | (+) | (+) | + | + | - | - | - | - | - | - | 100.0 |
| 36 | NTih | e | + | + | + | - | - | - | - | - | - | 100.0 |
| 11 | NTih | + | + | + | (+) | - | - | - | - | - | (+) | 90.0 |
| 5 | NTih | + | + | + | + | - | (+) | (+) | - | - | - | 80.0 |
| 12 | NTih | + | + | + | + | (+) | (+) | - | - | - | - | 80.0 |
| 39 | NTih | (-) | (-) | (+) | (+) | - | - | - | - | - | - | 80.0 |
| 30 | NTih | (-) | (-) | + | + | - | (+) | - | - | - | - | 70.0 |
WN = West Nile; TBE = tick-borne encephalitis; YF = yellow fever; DEN = dengue; neg. = negative; unspec. = unspecific. x/x = IgM/IgG result: - = correct negative result; (-) = false negative result without meaning; + = correct positive result; (+) = weak positive result; e = equivocal result; ind. = indetermined. -* = negative for WN virus, but other flavivirus detected; -# = negative for WN virus, but unspecific reaction detected. Results marked in bold mean false negative/positive results or non conclusive results which may have consequences for the decision of the clinician. ‡ Laboratory reported combined results: IgM tested by EIA and IgG tested by IFA. In other cases laboratories have reported combined results for IgM and IgG (single results).
EIA: Enzyme immunoassay; IFA: Immunofluorescence assay; NT: neutralisation test. Assays marked with the index "ih" are in-house assays. Assays marked in bold are commercial assays. Manufacturers: F = Focus Diagnostics Inc., Cypress, CA; USA, P = PanBio Ltd., Queensland, Australia.