Evaluation of two commercially available ELISAs for the diagnosis of Japanese encephalitis applied to field samples.
OBJECTIVE
To compare two commercially available kits, Japanese Encephalitis-Dengue IgM Combo ELISA (Panbio Diagnostics) and JEV-CheX IgM capture ELISA (XCyton Diagnostics Limited), to a reference standard (Universiti Malaysia Sarawak - Venture Technologies VT ELISA).


METHODS
Samples were obtained from 172/192 children presenting to a site in rural India with acute encephalitis syndrome.


RESULTS
Using the reference VT ELISA, infection with Japanese encephalitis virus (JEV) was confirmed in 44 (26%) patients, with central nervous system infection confirmed in 27 of these; seven patients were dengue seropositive. Of the 121 remaining patients, 37 (31%) were JEV negative and 84 (69%) were JEV unknown because timing of the last sample tested was <10 day of illness or unknown. For patient classification with XCyton, using cerebrospinal fluid alone (the recommended sample), sensitivity was 77.8% (59.2-89.4) with specificity of 97.3% (90.6-99.2). For Panbio ELISA, using serum alone (the recommended sample), sensitivity was 72.5% (57.2-83.9) with specificity of 97.5% (92.8-99.1). Using all available samples for patient classification, sensitivity and specificity were 63.6% (95% CI: 48.9-76.2) and 98.4% (94.5-99.6), respectively, for XCyton ELISA and 75.0% (59.3-85.4) and 97.7% (93.3-99.2) for Panbio ELISA.


CONCLUSIONS
The two commercially available ELISAs had reasonable sensitivities and excellent specificities for diagnosing JEV.
Lewthwaite
Penny
P
Brain Infections Group, University of Liverpool, Liverpool, UK. pennylewthwaite@doctors.org.uk
Shankar
M Veera
MV
Tio
Phaik-Hooi
PH
Daly
Janet
J
Last
Anna
A
Ravikumar
R
R
Desai
Anita
A
Ravi
V
V
Cardosa
Jane M
JM
Solomon
Tom
T
D000208:Acute Disease; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004672:Encephalitis, Japanese / Q000175:diagnosis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011933:Reagent Kits, Diagnostic; D012015:Reference Standards; D012680:Sensitivity and Specificity
D011933:Reagent Kits, Diagnostic