IGeneX single-step immunoblot nearly doubles early Lyme detection rate
IGeneX has published peer-reviewed data showing its FDA-cleared single-step immunoblot (IB) tests significantly outperform the standard two-tier testing (STTT) approach in detecting early-stage Lyme disease. The study, published in Microbiology Spectrum, analysed more than 1,100 serum samples and found the IgG IB test identified antibodies in 58.3% of CDC-classified stage 1 cases, compared with 30.0% for STTT, close to doubling the detection rate during the window when treatment is most effective.
The research was conducted by scientists at IGeneX and its R&D affiliate ID-FISH Technology, using well-characterised sample panels from the US Centers for Disease Control and Prevention and the Bay Area Lyme Foundation's Lyme Disease Biobank. Crucially, all testing was carried out under blinded conditions with independent statistical validation, lending the dataset greater weight than internal studies alone typically carry.
What makes the test different
Conventional STTT relies on a single Borrelia burgdorferi strain for antigen coverage, which researchers say limits sensitivity in early infection when antibody titres are still building. The IGeneX IB tests incorporate recombinant protein antigens drawn from multiple Borrelia species and strains found across the United States and Europe, including a proprietary Lyme Screen Antigen derived from immunodominant regions of the VlsE protein.
In addition to broader antigenic coverage, the single-step format eliminates the sequential enzyme immunoassay and Western blot workflow of conventional STTT, reducing turnaround time and laboratory complexity. When the IgG and IgM IB tests were used together, the combined detection rate for patients with confirmed erythema migrans lesions rose to 30.2%, against 20.6% for STTT. Discrepancy analysis identified 21 of 22 samples that were IB-positive but STTT-negative as confirmed true positives.
Specificity was also strong. Among 387 sera from individuals with potentially cross-reactive conditions, including autoimmune disorders, other tick-borne infections and viral illnesses, only one IgM false positive was recorded. IgM specificity was reported at approximately 99.7%, with IgG specificity at 99.4–100%.
"These findings represent a meaningful advancement in Lyme disease diagnostics, particularly given that commonly used FDA-cleared MTTT and STTT testing methods have been shown to miss 64–78% of early Lyme disease cases," said Jyotsna S. Shah, PhD, lead author and president of IGeneX.
Market context and regulatory position
The IB tests described in the study form the scientific basis for IGeneX's iDart IgG and IgM Immunoblot Tests, which have received 510(k) clearance from the FDA. That clearance is a meaningful commercial threshold: unlike laboratory-developed tests, 510(k)-cleared diagnostics can be marketed directly to hospital laboratories and reference labs without restriction to the originating CLIA site.
Lyme disease diagnostics is a segment with persistent unmet need. Estimates from the CDC suggest several hundred thousand new cases annually in the United States, and misdiagnosis in early-stage disease is a well-documented clinical problem. The current STTT framework dates to CDC guidance from the 1990s, and a number of companies, including large reference laboratory operators and speciality infectious-disease diagnostics developers, have been working on improved serological approaches. IGeneX's data, validated against CDC and independent biobank panels rather than proprietary samples only, may strengthen its position with health system procurement teams and payers evaluating alternatives to standard-of-care serology.
The next milestones to watch include broader clinical adoption, potential inclusion in updated CDC or IDSA diagnostic guidance, and whether the expanded antigen panel delivers consistent performance across geographically diverse Borrelia populations outside the study cohorts.