Evaluation of a Fully Automated Assay for Detection of Antidengue IgM Antibodies in a Nonendemic Area

Current French guidelines on the diagnosis of dengue infection recommend both nucleic acid testing and serology as tools for laboratory confirmation. This study aimed to evaluate the performance of the fully automated Virclia IgM assay for the diagnosis of dengue infection. Samples from patients with a suspicion of dengue were prospectively tested using the Virclia Dengue IgM assay (Vircell) and subsequently underwent additional investigations (dengue RT-PCR and conventional dengue IgM EIA) at the French Reference Center for Arboviruses. A total of 104 patients were included with a median age of 34.3 years old and a median time since symptom (TSS) of 6 days. Dengue RT-PCR was positive in 57 patients (54.8%). The agreement was excellent (90.5%; κ = 0.81) between RT-PCR and Virclia Dengue IgM assay on samples collected from Day 5 postsymptom onset. On these samples, the sensitivity and specificity of the Virclia IgM assay were 95.7% (95% CI: 84.7%-96.9%) and 96.4% (95% CI: 80.8%-100%), respectively. In addition, the agreement was also excellent between the Virclia Dengue IgM assay and the Euroimmun plate-based Dengue IgM ELISA (92.7%; κ = 0.85). In conclusion, the Virclia Dengue IgM assay showed a good performance in the diagnosis of dengue infection and can be recommended in addition to nucleic acid testing to broaden the diagnostic window. The automation coupled with the monotest format is well-adapted for nonendemic areas.