New Bay Area Lyme Foundation Study Shows Common FDA-Cleared Lyme Tests Miss 64-78% of Early Cases, Underscores Urgent Need for Improved Diagnostics

Research published in the Journal of Clinical Microbiology

PORTOLA VALLEY, Calif., April 21, 2026 (GLOBE NEWSWIRE) -- Bay Area Lyme Foundation, a national nonprofit and leading sponsor of tick-borne disease research in the US, today announced the publication of new research in the Journal of Clinical Microbiology based on data from its Lyme Disease Biobank. The study found that the commonly used FDA-cleared diagnostic testing methods available to providers and major national diagnostic laboratories are highly insensitive and miss 64-78% of early Lyme disease cases, including those who present with the characteristic erythema migrans (EM) Lyme rash.

“This study demonstrates that common two-tiered Lyme tests, utilized for decades, often fail to detect early Lyme disease and are leaving patients behind, highlighting a critical need for improved medical education on the limitations of current diagnostics,” said Liz Horn, PhD, MBI, Principal Investigator of Lyme Disease Biobank and lead author of the study. “Our findings also add to the evidence that improved diagnostics, ideally those that directly detect the bacteria that cause Lyme disease, are urgently needed.”

This large-scale, head-to-head study comparing 2 standard two-tiered testing (STTT) and 2 modified two-tiered testing (MTTT) diagnostic algorithms (the commonly used Lyme disease diagnostic algorithms) confirms that the sensitivity of two-tiered testing algorithms is low among patients with early infection. For the 107 early Lyme disease cases evaluated, the various testing algorithms missed 64-78% of early Lyme cases. Overall, only 39% (42/107) of participants with early Lyme disease were STTT or MTTT positive by any of the 4 algorithms.

The study found that current Lyme disease diagnostic algorithms (STTT and MTTT), which rely on antibody detection rather than direct detection of the bacteria, have limited accuracy in early infection—particularly within the first one to two weeks, when antibodies may not yet be detectable—potentially contributing to missed or delayed diagnoses. While modified two-tiered testing (MTTT) showed higher sensitivity than standard two-tiered testing (STTT), including in a subset of laboratory-confirmed cases (82% vs. 53–69%), overall performance remained suboptimal, especially in the earliest stage of infection. The authors also observed variability across testing methods, with some samples testing positive by one algorithm and negative by another, and noted that test positivity was more likely in participants with symptoms and increased with longer duration of illness or rash. In participants with EM duration of less than 1 week, neither algorithm was likely to be positive.

“It’s important for clinicians to understand the limitations of STTT and MTTT in early disease, and to rely on clinical judgment when evaluating patients with suspected early Lyme disease, particularly when there has been potential recent tick exposure and compatible signs and symptoms are present, to ensure prompt treatment,” said John A. Branda, MD, Associate Professor, Harvard Medical School and Director, Clinical Microbiology Laboratory, Massachusetts General Hospital and a 2015 Bay Area Lyme Emerging Leader Award winner. “Our study was enabled by a robust collection of samples from Lyme Disease Biobank that included clinical information about patient signs and symptoms. It builds upon previous studies and highlights an urgent need for novel diagnostics for early Lyme disease that do not rely on antibody detection.”

This real-world study uses well-characterized, geographically diverse samples from Lyme Disease Biobank, which enrolled 107 participants with signs and symptoms of early Lyme disease, along with 144 control participants at clinical sites in East Hampton, New York, and several locations in Wisconsin, which are endemic areas for Lyme disease, between 2017 and 2020. Of the 107 cases, 93 (87%) presented with a suspected EM, and 14 (13%) presented with constitutional symptoms compatible with early Lyme disease but without the sign of EM rash.

About Lyme disease
Lyme disease is the most common vector-borne infection in the US and can cause debilitating long-term symptoms. Transmitted by the bite of an infected tick, and potentially from mother to unborn baby, Lyme disease is often misdiagnosed, making timely treatment difficult. As a result, up to two million Americans may be living with long-term complications. Each year, approximately 500,000 Americans are diagnosed with Lyme disease, far more than new cases of HIV/AIDS, West Nile virus, tuberculosis, or malaria combined. A 2022 BMJ Global Health analysis found that about 1.15 billion people worldwide have or previously had an infection with Lyme Borrelia, highlighting the widespread and growing public-health impact of this disease.

About Lyme Disease Biobank
Lyme Disease Biobank (LDB), a program of Bay Area Lyme Foundation, is a non-profit organization working to accelerate research of Lyme disease and other tick-borne infections. With a collection of biological specimens from more than 1,250 participants, including blood, serum, plasma, urine and tissue, LDB provides much-needed samples to approved researchers working to better understand tick-borne diseases and develop improved diagnostic tests and therapeutics. Blood and urine samples are collected from the Northeast, Upper Midwest and West Coast areas of the US, and tissue samples are collected throughout the country. Researchers interested in obtaining samples should visit www.lymebiobank.org or contact info@lymebiobank.org.

About Bay Area Lyme Foundation
Bay Area Lyme Foundation, a national organization committed to making Lyme disease easy to diagnose and simple to cure, is the leading public charity sponsor of innovative Lyme disease research in the US. A 501(c)(3) organization based in Silicon Valley, Bay Area Lyme Foundation collaborates with world-class scientists and institutions to accelerate medical breakthroughs for Lyme disease. It is also dedicated to providing reliable, fact-based information so that prevention and the importance of early treatment are common knowledge. Historically, a pivotal donation from the LaureL STEM fund covered all overhead costs through 2024. In 2023, a Bay Area Lyme Endowment was formed, which allows for 100% of all donor contributions to Bay Area Lyme Foundation to go directly to research and prevention programs in perpetuity. For more information about Lyme disease or to get involved, visit www.bayarealyme.org or call us at 650-530-2439.

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