External quality assessment of dengue and chikungunya diagnostics in the Asia Pacific region, 2015

Abstract

ObjectiveTo conduct an external quality assessment (EQA) of dengue and chikungunya diagnostics among national-level public health laboratories in the Asia Pacific region following the first round of EQA for dengue diagnostics in 2013.MethodsTwenty-four national-level public health laboratories performed routine diagnostic assays on a proficiency testing panel consisting of two modules. Module A contained serum samples spiked with cultured dengue virus (DENV) or chikungunya virus (CHIKV) for the detection of nucleic acid and DENV non-structural protein 1 (NS1) antigen. Module B contained human serum samples for the detection of anti-DENV antibodies.ResultsAmong 20 laboratories testing Module A, 17 (85%) correctly detected DENV RNA by reverse transcription polymerase chain reaction (RT–PCR), 18 (90%) correctly determined serotype and 19 (95%) correctly identified CHIKV by RT–PCR. Ten of 15 (66.7%) laboratories performing NS1 antigen assays obtained the correct results. In Module B, 18/23 (78.3%) and 20/20 (100%) of laboratories correctly detected anti-DENV IgM and IgG, respectively. Detection of acute/recent DENV infection by both molecular (RT–PCR) and serological methods (IgM) was available in 19/24 (79.2%) participating laboratories.DiscussionAccurate laboratory testing is a critical component of dengue and chikungunya surveillance and control. This second round of EQA reveals good proficiency in molecular and serological diagnostics of these diseases in the Asia Pacific region. Further comprehensive diagnostic testing, including testing for Zika virus, should comprise future iterations of the EQA.

A review of dengue diagnostics and implications for surveillance and control

“…Measuring anti-dengue immunoglobulin M (IgM) and/or IgG antibodies using an antibody-capture enzyme-linked immunosorbent assay (ELISA) is the most widely used method of confirming dengue diagnosis, because it is relatively easy to perform compared with techniques such as nucleic acid detection, although laboratory equipment and trained staff are still needed. 15,16 However, increases in antibody titres are not immediate, meaning IgM ELISAs are <50% sensitive for at least 4 d after symptom onset in primary infection, reducing their usefulness in clinical management. 17 Secondary cases, which are more severe, have lower IgM titres, undetectable in >20% of cases.…”

External quality assessment for arbovirus diagnostics in the World Health Organization Western Pacific Region, 2013–2016: improving laboratory quality over the years

“…There was no round of EQA in 2014 due to logistic and technical review of the first round for improvement of subsequent iterations. In 2015, a second round of EQA, not only for dengue but also chikungunya diagnostics, was prepared by EHI ( 9 ) and involved 24 laboratories, including 19 in the Region and five in the WHO South-East Asia Region. In 2016, in succession to the two regional programmes, WHO organized the first global EQA programme for arbovirus diagnostics.…”

Chikungunya Virus

“…Commercially available kits are of variable quality. 48 PCR assays with favorable performance characteristics are documented in the literature and becoming commercially available for clinical use in other countries; however, they can only be obtained for research use in the United States. Good immunoassays for CHIKV-specific IgM in patient serum are less reliable and available.…”