The performance of 2 commercial serologic tests for diagnosing Zika virus was deemed suboptimal, according to data published in Emerging Infectious Diseases.

Investigators evaluated both the Euroimmun and Dia.Pro serologic tests for detection of Zika virus immunoglobulin (Ig)M and IgG using a panel of 199 samples from a flavivirus endemic region, 90 of which were positive for Zika virus and 109 of which were negative for Zika virus. A further 300 sequential specimens sampled over a 10-month period postinfection were monitored to determine Zika virus antibody kinetics.

The sensitivity for Zika virus IgM was low, specifically for the Euroimmun test at 49% (95% CI, 38%-60%). Dia.Pro IgM sensitivity was 69% (95% CI, 59%-79%), but IgM was detectable for months with the Dia.Pro assay. Specificity for IgM for Euroimmun and Dia.Pro was 99% (95% CI, 97%-100%) and 96% (95% CI, 92%-100%), respectively.

Specificity for Zika IgG assays was also low, 62% (95% CI, 53%-71%) for Dia.Pro and 70% (95% CI, 61%-79%) for Euroimmun. Sensitivity for Euroimmune was 71% (95% CI, 92%-100%) and 79% (95% CI, 70%-88%) for Dia.Pro. Investigators also reported that the findings were strongly influenced by epidemiologic context.

One limitation to this study was the confirmation of Zika-positive samples using real-time polymerase chain reaction, meaning these were all symptomatic cases. If antibody levels differ from symptomatic to asymptomatic, as is the case for dengue, the performance of antibody kinetics may be considerably different for asymptomatic cases.

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According to investigators, this work, “highlights the complexity of interpreting serologic assays in areas where various arboviruses cocirculate.” The study authors also believe that accurate analysis of the performance of assays is required to adapt and interpret algorithms. They recommend that further studies are needed to identify specific biomarkers of each flavivirus for diagnosis after the acute phase of the disease.

Reference

Matheus S, Talla C, Labeau B, et al. Performance of 2 commercial serologic tests for diagnosing Zika virus infection. Emerg Infect Dis. 2019;25:1153-1160.