Differential Diagnosis of Japanese Encephalitis Virus Infections with the Inbios JE Detect™ and DEN Detect™ MAC-ELISA Kits.

Japanese encephalitis virus (JEV) is the leading cause of pediatric viral neurological disease in Asia. The JEV-specific IgM antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA) in cerebrospinal fluid (CSF) and serum is the recommended method of laboratory diagnosis, but specificity of JEV MAC-ELISA can be low due to cross-reactivity. To increase the specificity of the commercially available JEDetect™ MAC-ELISA (JEDetect), a differential testing algorithm was developed in which samples tested by JEDetect with positive results were subsequently tested by the DENDetect™ MAC-ELISA (DENDetect) kit, and results of both tests were used to make the final interpretation. The testing algorithm was evaluated with a reference panel of serum and CSF samples submitted for confirmatory testing. In serum, the false Japanese encephalitis (JE) positive rate was reduced, but sequential testing in CSF resulted in reduced JE specificity, as true JEV+ CSF samples had positive results by both JEDetect and DENDetect and were classified as JE- (dengue virus [DENV]+). Differential diagnosis of JE by sequential testing with JEDetect and DENDetect increased specificity for JE in serum, but more data with CSF is needed to make a final determination on the usefulness of this testing algorithm for CSF.