Episode 568: Lyme Disease Testing Is Failing Patients: Dr. Liz Horn Explains Why (And What Comes Next)
Tick Boot Camp
In this critical episode with special guest co-host Ali Moresco, we sit down with Dr. Liz Horn, Principal Investigator of the Lyme Disease Biobank, to break down her latest research:
👉 Evaluation of standard and modified two-tiered testing algorithms using well-characterized early Lyme disease samples
This study takes a hard look at the current FDA-cleared Lyme testing system — and the findings are clear:
👉 Most early Lyme disease cases are being missed
Dr. Horn explains why this is happening, what it means for patients, and why clinical judgment — not just testing — must guide early diagnosis and treatment.
🔬 The Study at the Center of This Episode
📄 View Dr. Liz Horn’s Research Publications
📊 Study Focus:
Compared Standard Two-Tier Testing (STTT) vs Modified Two-Tier Testing (MTTT)
Used real-world patient samples from early Lyme cases
Evaluated four FDA-cleared diagnostic algorithms
Focused primarily on patients within the first ~3 weeks of symptoms
🚨 Key Finding: Early Lyme Testing Is Deeply Flawed
Only 22–36% of early Lyme cases tested positive
That means 64–78% of cases were missed
Most people with early Lyme disease will test negative
📌 Easy-to-share summary for doctors and patients: New Bay Area Lyme Foundation Study Shows Common FDA-Cleared Lyme Tests Miss 64–78% of Early Cases
🧠 Why These Tests Fail
Current tests detect antibodies, not the bacteria itself
The immune system needs time to produce detectable antibodies
Early infections often test negative because the immune response has not developed yet
The two-tier system adds additional opportunities for false negatives
👉 Core issue: Testing measures the body’s response, not the infection
⏱️ The Critical Timing Problem
Within 1 week of symptoms, tests are almost always negative
Around 2 weeks, detection improves slightly
After 3–4 weeks, sensitivity increases but is still unreliable
Testing does not become fully accurate at any point
👉 Key insight: Testing remains inconsistent even after the early window
🎯 Even “Classic” Lyme Cases Are Missed
Patients with erythema migrans (EM rash) often tested negative
Very few patients present with a classic bullseye rash
A visible rash does not guarantee a positive test result
👉 Key takeaway: You can have Lyme and still test negative
⚠️ Major Issue: Test Inconsistency
The same patient can receive different results depending on the test used
One algorithm may detect Lyme while another misses it
Results depend on timing, immune response, and test design
👉 Result: Testing cannot reliably confirm or rule out Lyme disease
🧍♂️ Who Actually Tests Positive?
Patients with more symptoms were more likely to test positive
Longer duration of illness increased likelihood of detection
Stronger immune responses improved test sensitivity
👉 Translation: Testing tends to detect later-stage immune response, not early infection
💊 After Treatment: Testing Becomes Even Less Useful
This study focused on early Lyme within the first ~3 weeks, where testing already performed poorly
At approximately 3 months post-treatment, less than 5% of patients who still had an active infection tested positive
These patients were originally diagnosed with early Lyme and many continued to have symptoms consistent with active or ongoing infection
👉 Why this happens:
Antibiotics can suppress antibody production
The immune response may no longer be detectable
The bacteria may persist in tissues rather than circulating in blood
👉 Critical takeaway:
Patients may still have an active infection or ongoing disease process and test negative
👉 Bottom line:
Testing is unreliable early in infection
Testing remains unreliable after treatment
A negative test does not rule out Lyme disease at any stage
🧬 Another Challenge: Lyme Leaves the Blood
Borrelia bacteria can move into tissues
Blood-based tests may miss active infection
Direct detection becomes more difficult over time
👉 This is why antibody testing is used, despite its limitations
🧩 Bigger Insight From This Study
Current Lyme testing cannot reliably diagnose early infection
Diagnosis must include symptoms, exposure history, and clinical judgment
Over-reliance on testing leads to missed diagnoses and delayed care
🚀 What Comes Next (Hope from the Research)
Development of direct detection tests that identify the bacteria
Cell-free DNA testing approaches
AI and machine learning diagnostics
Multiplex testing targeting multiple markers
Urine-based diagnostic innovations
👉 These advances aim to replace outdated antibody-based testing
🧑⚕️ Education Gap (Major Takeaway)
Many clinicians are not trained on the limitations of Lyme testing
Negative tests are often incorrectly used to rule out disease
This contributes to delayed diagnosis and treatment
📚 Resource for clinicians and patients: VectorWise CME – Lyme Disease Education
💡 What This Means for You
A negative test does not rule out Lyme disease
Early symptoms are more important than lab results
Treatment decisions should not rely solely on testing
Follow-up care remains essential even after treatment
👉 Most important: Trust your symptoms and advocate for care
💚 Final Message
This study confirms what many patients already experience:
The testing system is flawed
Early infections are frequently missed
Patients can remain sick while testing negative
But progress is happening.
👉 Better diagnostics are on the horizon
You are not alone. Your experience is real.Healing is possible.
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