Serologic Diagnostic Tests Evaluated for Chikungunya Virus

The disease caused by the mosquito borne Chikungunya virus (CHIKV) is clinically characterized by sudden-onset fever and severe arthralgia, which may persist for weeks, months, or years after the acute phase of the infection.

One serologic testing method for CHIKV is the indirect fluorescent antibody (IFA) technique and although IFA tests have good sensitivity and specificity for CHIKV, this method requires specific material that may not be available in diagnostic laboratories worldwide.

Scientists at the French Armed Forces Biomedical Research Institute (IRBA; Marseille, France) obtained two sets of serum samples for testing: panel A with 23 samples)and panel B with 30 samples. The samples had been submitted to IRBA for arbovirus testing from 2005 to 2014. The serum samples were chosen on the basis of their reactivity against CHIKV and other genetically or clinically related arboviruses.

The team evaluated valuated four commercially available serologic tests that are approved for CHIKV testing by the European Commission. Two of the tests were rapid diagnostic tests (RDTs) for CHIKV immunoglobulin M (IgM): SD Bioline Chikungunya IgM (Standard Diagnostics Inc.; Yongin-si, Republic of Korea) and OnSite Chikungunya IgM Combo Rapid Test (CTK Biotech Inc.; San Diego, CA, USA). The two other tests were enzyme-linked immunosorbent assays (ELISAs) for the detection of CHIKV IgM and IgG: Chikungunya IgM μ-capture ELISA and Chikungunya IgG Capture ELISA (IBL International; Hamburg, Germany) and Anti-Chikungunya Virus ELISA IgM test and Anti-Chikungunya Virus ELISA IgG test (Euroimmun; Lübeck, Germany).

The SD Bioline RDT showed poor sensitivity of 30% and specificity of 73% for CHIKV in panel A samples, and 39% and 57% of the results were false negative and false positive, respectively. The CTK kit showed 93% specificity and 20% sensitivity for CHIKV in panel A samples, and 36% and 33% of the results were false negative and false positive, respectively. The ineffectiveness of the RDT kits was demonstrated by panel A test results, so panel B was not tested. The specificity and sensitivity of the ELISAs for the samples was greater than 70%.

The authors concluded that the commercial RDTs that were compared with in-house ELISAs from two National Reference Centers for Arboviruses performed poorly. The two ELISAs that were tested had better sensitivity and specificity than the RDTs; however, they had a non-negligible number of false negative and false-positive results. Although the pilot study used a small number of samples, the findings show the importance of evaluating commercial diagnostic kits and published protocols before using such tools in clinical settings. The study was published online in the December 2014 issue of the journal Emerging Infectious Diseases.

Related Links:
French Armed Forces Biomedical Research Institute 
Standard Diagnostics Inc. 
CTK Biotech Inc.