Viramed has developed a novel IgM and IgG immunoblot assay, the B. burgdorferi B31 + VlsE ViraChip (VC), which utilizes ELISA principles in a microarray format. The individual IgM and IgG VCs utilize purified B. burgdorferi VlsE and other antigens, identical to those on the VS, immobilized at defined spots on a microarray. The IgG and IgM microarrays are affixed to the bottom of 96-well microtiter plates, enabling rapid processing and objective analysis on automated ELISA instruments and imaging systems.
Here, we compared performance of the VC IgM/IgG assays to the VS IgM/IgG, the MarDx B. burgdorferi MarBlot IgM/IgG western blots (MB; Trinity Biotech, Carlsbad, CA) and the C6 ELISA.
Methods: 188 serum samples submitted to Mayo Medical Laboratories (Rochester, MN) for Lyme disease testing were tested by all four assays and qualitative results were correlated.
Results: Compared to the VS and MB IgM blots, the VC IgM assay showed positive, negative and overall percent agreement of 80.0%, 81.7%, 81.4% and 100.0%, 71.7%, 72.3%, respectively. The VC IgG assay showed positive, negative and overall agreement of 93.0%, 95.2%, 94.7% and 74.6%, 97.7%, 90.4% in comparison to the VS and MB IgG blots, respectively. The VC IgG VlsE results showed positive, negative and overall agreement of 74.4%, 94.9% and 85.1%, respectively, with the C6 ELISA. Only 2/23 C6 positive/VC IgG VlsE negative samples were positive by VC, VS, or MB IgG blots, while 5/23 were positive by VC, VS, or MB IgM blots.
Conclusion: The VC IgG assay has excellent correlation with the VS IgG immunoblot and good correlation with the MB IgG blot. Also, the VlsE result from the VC IgG microarray demonstrated excellent correlation with both the VS and MB IgG blots, suggesting that the VC IgG VlsE result may be used as the initial screen in the two-tiered testing algorithm. Finally, the VC IgM microarray demonstrated limited correlation to both the VS and MB IgM blots, suggesting that further development to detect this analyte may be warranted.
E. Theel, None