Nearly 1 in 3 Patients with Suspected Lyme Disease are Co-Positive for Other Tick-Borne Pathogens, Finds Study by Quest Diagnostics

A JAMA Network Open study of 193,260 U.S. patients found that 29.5% of people with Lyme disease antibodies also had antibodies to at least one additional tick-borne pathogen, versus 5.5% among those without Lyme antibodies. Co-seropositivity was highest in the Northeast at 31.1%, with Babesia antibodies co-detected in 18.5% of Lyme-seropositive patients in the region. The Quest Diagnostics and UNC research supports broader tick-borne testing, though serology results may reflect past exposure rather than active infection.

Analysis

The investable read-through for DGX is test-mix rather than volume: broader reflex or panel ordering can lift revenue per requisition and improve laboratory asset utilization with little incremental fixed cost. Yet tick-borne testing is too seasonal and geographically concentrated to alter consolidated earnings meaningfully; even a strong regional panel adoption cycle is more likely a modest margin tailwind than a guidance-moving event. Labcorp (LH) has comparable capability, limiting any durable pricing power unless DGX converts its dataset into preferred-provider protocols with large health systems or payers.

The key near-term catalyst is the autumn ordering season and whether commercial-payer policies or clinical guidelines begin favoring multi-pathogen testing after an initial Lyme workup. The central risk is that antibody co-detection does not establish active disease, leaving clinicians and payers reluctant to expand panels because of false-positive follow-up costs and utilization-management scrutiny. Over 6-18 months, warmer-weather geographic expansion could create a recurring specialty-infectious-disease testing category, but that requires evidence of incremental reimbursed tests—not just published seroprevalence—and would be competed away by LH and hospital laboratories.

Consensus may over-credit the publication as a direct demand catalyst. Diagnostic utilization usually changes only after guideline, payer, or electronic-order-set adoption; absent those triggers, this is primarily reputational support for DGX's infectious-disease franchise rather than a reason to revise estimates.

Key Decisions for Investors

• No standalone DGX trade on this release; maintain existing exposure only. Reassess after 3Q/4Q results for disclosed infectious-disease test-volume growth, revenue-per-requisition improvement, or management commentary tying panel adoption to reimbursement.
• Set a 1-3 month monitoring trigger for DGX: initiate a modest long only if seasonal testing strength is accompanied by raised organic-revenue or margin guidance; target a 5-8% relative upside versus the diagnostics group, with exit if guidance is unchanged and utilization commentary remains nonspecific.
• For a structural-testing thesis, prefer a market-neutral expression only after evidence of differentiated payer contracts: long DGX / short LH in equal dollar amounts. Falsify if LH reports equivalent panel uptake or DGX fails to demonstrate superior revenue-per-requisition growth for two consecutive quarters.
• Watch CMS/commercial-payer coverage updates and Northeast health-system order-set changes. A restrictive coverage decision or emphasis on confirmatory testing would undermine the panel-mix thesis and could create modest downside risk to DGX's premium multiple.