A Systematic Evaluation of IgM and IgG Antibody Assay Accuracy in Diagnosing Acute Zika Virus Infection in Brazil: Lessons Relevant to Emerging Infections
Raquel Medialdea-Carrera, Flavia Levy, Priscila Castanha, Patricia Carvalho de Sequeira, Patricia Brasil, Lia L. Lewis-Ximenez, Lance Turtle, Tom Solomon, Ana Maria Bispo de Filippis, David W. Brown, Michael J. Griffiths
Abstract
= 236) were collected before ZIKV was present in Brazil (≤2013). Among serum samples collected ≥7 days from symptom onset, PRNT exhibited the highest accuracy (93.7%), followed by the Euroimmun IgG ELISA (77.9%). All IgM assays exhibited lower accuracy (<75%). IgG was detected more consistently than IgM among ZIKV cases using Euroimmun ELISAs (68% versus 22%). Anti-dengue virus IgM ELISA was positive in 41.1% of confirmed ZIKV samples tested. The Euroimmun IgG assay, although misdiagnosing 22% of samples, provided the most accurate ELISA. Anti-ZIKV IgG was detected more reliably than IgM among ZIKV patients, suggesting a secondary antibody response to assay antigens following ZIKV infection. Antibody ELISAs need careful evaluation in their target population to optimize use and minimize misdiagnosis, prior to widespread deployment, particularly where related viruses cocirculate.