Table 5. Specificity of the ReaScan TBE IgM rapid testa evaluated by potentially interfering serum samples and potentially cross-reactive IgM resulting from other flavivirus infections (n = 165 samples).
| Type of samples | ReaScana result | Total | Specificity (95% CI) |
||
|---|---|---|---|---|---|
| TBE positive | TBE equivocalb | TBE negative | |||
| Samples with potentially interfering agents (from patients with A. phagocytophilum, CMV, EBV, HSV and VZV infections)c |
0 | 3 | 80 | 83 | 96.4% (89.8–99.3%) |
| Samples from patients with other flavivirus/togavirus (DENV, JEV, WNV, YFV, ZIKV, CHIKV) infections/vaccinationsd | 1e | 0 | 81 | 82 | 98.8% (93.4–100%) |
A. phagocytophilum: Anaplasma phagocytophilum; CHIKV: Chikungunya virus; CI: confidence interval; CMV: cytomegalovirus; DENV: dengue virus; EBV: Epstein–Barr virus; HSV: herpes simplex virus; JEV: Japanese encephalitis virus; TBE: tick-borne encephalitis; VZV: varicella zoster virus; WNV: West Nile virus; YFV: yellow fever virus; ZIKV: zika virus.
TBE: tick-borne encephalitis.
a ReaScan TBE IgM rapid test (Reagena, Toivala, Finland).
b The equivocal results were calculated as false positives.
c Among these 83 samples, 66 had tested TBE IgM negative by Enzygnost Anti-TBE virus ELISA test (Siemens GmbH, Marburg, Germany) and 17 had tested negative by TBE virus neutralisation test.
d Among these 82 samples, four had tested TBE IgM negative by Enzygnost Anti-TBE virus ELISA test (Siemens GmbH, Marburg, Germany), 27 were from individuals with no medical reason to check for TBEV infection and 51 had tested negative by TBE virus neutralisation test.
e This sample was from a YFV vaccinated individual.