Quest Diagnostics Publishes Findings on Tick‑Borne Co‑Seropositivity, Prompting Reevaluation of Diagnostic Protocols

Quest Diagnostics, a leading clinical laboratory services provider, has released the results of a large serological study that examined nearly 200,000 U.S. patients tested for tick‑borne diseases between 2021 and 2025. The analysis, published in JAMA Network Open, found that individuals with antibodies to the Lyme‑disease bacterium Borrelia burgdorferi were significantly more likely to have antibodies to one or more additional tick‑borne pathogens. In the cohort, roughly thirty percent of those with Lyme‑disease antibodies also showed evidence of exposure to other organisms, compared with a much lower rate among those without Lyme‑disease antibodies.

The study highlighted that co‑seropositivity is most common for pathogens transmitted by the blacklegged tick, such as Babesia microti and Anaplasma phagocytophilum. The pattern of co‑exposure varied across the country, with the Northeast showing the highest rates, reflecting the regional distribution of tick vectors and host species. Seasonal trends were evident, with a majority of tests performed during the warmer months when tick activity peaks.

Quest Diagnostics emphasized that the findings underscore the importance of comprehensive testing when evaluating patients with suspected tick‑borne illness. Overlapping clinical symptoms among Lyme disease, anaplasmosis, and babesiosis can lead to missed diagnoses if only single‑pathogen testing is performed. The company’s panel of antibody tests, designed to detect multiple tick‑borne agents, aims to improve diagnostic accuracy and guide appropriate treatment choices.

The study’s use of real‑world data from a broad national sample provides a robust view of tick‑borne co‑exposure patterns, although the authors noted that serologic evidence may reflect past exposure rather than active infection. The company continues to offer laboratory services that support clinicians in diagnosing and managing tick‑borne diseases.