DotBlot testing for Lyme disease is an EIA membrane strip format that allows separate results for IgG and IgM in less than two hours.
The IgG and IgM tests are designed to run simultaneously and, like other ELISA assays, use a whole borrelial antigen to screen. But like Western blots, the DotBlot tests also detect antibodies to other specific borrelia proteins, which can improve diagnostic accuracy.
Unlike Western blots, Borrelia DotBlot tests are manufactured using characterized and standardized levels of purified proteins including recombinants to assure lot-to-lot reproducibility. The test gives separate results for whole borrelia, HMW (P83-100), Flagellin (P41), BmpA (P39) and OspC antigens.
These products do not rely on OspA reactivity for interpretation. Instead, serodiagnosis is based on the response to selected recombinant and purified antigens other than OspA. These other Borrelia proteins are not in the vaccine. Therefore, the product can prove useful for vaccinated subjects since responses to OspA protein should not effect serodiagnosis.
The following specific borrelia antibodies are tested for in the DotBlot products. HMW, a high molecular weight protein (83-100kD), whose antibodies are usually IgG, appears late in the progress of the disease. Flagellin is a predominant antibody response in Lyme disease, and levels used in these tests are adjusted to assure minimal cross-reactivity with other spirochetes and bacteria. Recombinant p39, a dominant immuno-reactive protein, can be one of the most specific indicators of borrelia infection. Anti-OspA appears early during the primary infection. Used simultaneously, DotBlot IgG and IgM allow interpretation of the patients seroreactivity.
Data for these tests was obtained from sera of culture confirmed patients. Specificity was checked with large batches of negative sera, and the product demonstrates a specificity of greater than 99 percent. A recent study showed 100 percent correlation with expected patient results of proficiency samples from the last two years. Additional testing against the CDC Borrelia panel of samples showed that testing using the GenBio ImmunoDOT yields essentially the same results as obtained by the CDC. Copies of this report are available.
Keyword: reagent, Lyme disease