by Timothy Sellati, Ph.D., Chief Scientific Officer, GLA
Global Lyme Alliance’s Chief Scientific Officer offers perspective on the new FDA approved Lyme disease blood test.
The U.S. Food and Drug Administration recently cleared the Quidel company’s Sofia Lyme Fluorescence Immunoassay (FIA) to be run on Sofia 2, a next-generation version of their Fluorescent Immunoassay Analyzer. The Sofia Lyme FIA employs immunofluorescence for the rapid detection of human IgM and IgG antibodies to Borrelia burgdorferi in serum and plasma specimens from patients suspected of Lyme disease. This qualitative test is intended for use as a rapid aid (10 minutes) in the diagnosis of Lyme disease. According to Quidel, all positive results for IgM and/or IgG antibodies using Sofia Lyme FIA should be further tested by a corresponding second-tier West-ern
The assay uses a bidirectional test strip format to detect both IgM and IgG antibodies to B. burgdorferi. One side of the test strip detects IgM antibodies to multiple B. burgdorferi antigens and the other side of the test strip detects IgG antibodies using as little as 30 µL serum/plasma from a suspected Lyme disease patient. According to Erica Lovell, Quidel’s technical support manager, ”We are using a mixture of novel Lyme antigens that are specific to human IgM and IgG response. We have moved away from the more traditional Enzyme Immunoassay methods that used crude antigens. Our novel antigen mixtures have enabled us to maximize our sensitivity while maintaining a high degree of sensitivity.” This rapid test is not intended as a stand-alone determinant of B. burgdorferi infection status and a negative result does not preclude infection with B. burgdorferi. Nevertheless, a negative result would save time and expense insofar as testing by the more elaborate and second-tier Western immunoblot assay, which requires subjective interpretation of results, would be contraindicated.
Despite the rapid results obtained using the Sofia Lyme FIA, as pointed out in another GLA POV entitled “Advances in Serodiagnostic Testing for Lyme Disease Are at Hand,” improvements in serologic testing methods or protocols will not differentiate active infection from past exposure. Thus, ideally, use of NextGen tests like Quidel’s Sofia Lyme FIA will be coupled with other diagnostic methods to directly detect the presence of B. burgdorferi and other tick-borne pathogens in patient samples, thereby allowing discrimination between active vs. past infections. GLA is a leader in actively supporting research efforts to develop such direct detection methods.
Timothy J. Sellati, PH.D. is Chief Scientific Officer at Global Lyme Alliance
As GLA’s Chief Scientific Officer, Dr. Sellati leads GLA’s research initiatives to accelerate the development of more effective methods of diagnosis and treatment of Lyme and other tick-borne diseases.