Discrepancies in widely used serological methods to detect Borrelia infections may cause missed Lyme diagnoses

This study demonstrates that significant variability in sensitivity among widely used serological assays leads to missed Lyme disease diagnoses, highlighting the critical need for standardized testing protocols and the routine integration of longitudinal sample comparisons to improve diagnostic accuracy and patient outcomes.

The Gist

Imagine you are trying to find a specific type of lost key in a giant, messy room. This key represents a Lyme disease infection inside a person's body. To find it, doctors use special "metal detectors" (blood tests) that beep when they sense the key.

This paper is like a report from a team of detectives who realized that not all metal detectors are created equal. Some are high-tech, super-sensitive devices, while others are old, rusty models that often miss the key entirely.

Here is the story of their findings, broken down simply:

1. The Problem: The "Rusty Detectors"

Lyme disease is caused by a bacteria called Borrelia. When a person gets infected, their body makes "wanted posters" (antibodies) to fight it. Doctors look for these posters in the blood.

The researchers looked at a group of outdoor workers (like forest rangers and gardeners) who get tested every year because they are at high risk of tick bites. They took blood samples from people who definitely had the infection (because their "gold standard" test found it) and ran them through three different types of commercial blood tests:

• The Gold Standard: A combination of two specific tests (EUROIMMUN and ZEUS).
• The Popular Choice: A very common, automated test (Diasorin).
• The Other Contender: Another popular test (SERION).

2. The Big Reveal: Missing the Mark

The results were shocking. It was like sending the same lost key through three different metal detectors:

• The Gold Standard found the key 97% of the time.
• The Popular Choice (Diasorin) only found it 70% of the time.
• The Other Contender (SERION) found it 84% of the time.

The Analogy: Imagine you are looking for a needle in a haystack.

• The Gold Standard is a magnet that pulls out almost every needle.
• The Popular Choice is a weak magnet that misses 3 out of every 10 needles.
• The Other Contender misses about 1 out of every 6 needles.

3. The Real-World Consequences: The "Silent" Infections

The most scary part of the study wasn't just the numbers; it was the real people affected.

• The "False Negative" Trap: In several cases, a person went to their regular doctor, got tested with the "Popular Choice" machine, and was told, "You are fine, no Lyme disease." But when the researchers ran the same blood through their "Gold Standard" machine, it screamed, "Yes! Infection here!"
• The Case of the Teenager: One teenager had fatigue and joint pain. The local hospital tested them with the "Popular Choice" machine. It gave a confusing result (IgM positive, IgG negative) that the hospital ignored. The researchers re-tested the same blood and found clear evidence of a new infection. The teen was finally treated with antibiotics and felt better.
• The "New" Infections: The study found 6 people who had just been infected recently. Because the "Popular Choice" test wasn't sensitive enough, it missed these new infections completely. If these people hadn't been screened by the researchers, they would have been sent home untreated, potentially leading to severe long-term damage to their joints or nerves.

4. Why Does This Happen?

Why do some tests miss the infection?

• Different Scents: Think of the bacteria as a criminal who changes their disguise. Different tests look for different "disguises" (parts of the bacteria). Some tests look for the disguise the criminal wears right now (early infection), while others only recognize the disguise they wore years ago. If the test only looks for the old disguise, it misses the new criminal.
• The "One Band" Rule: Some tests require a lot of evidence to say "Yes." The researchers found that sometimes, a test sees just one tiny clue (a single band on a blot) and says, "That's not enough, it's negative." But the researchers argued that in early infection, that single clue is actually the smoking gun!

5. The Solution: Better Tools and Smarter Habits

The authors are calling for two major changes:

1. Upgrade the Tools: We need to agree on which "metal detectors" are the best. They suggest using the more sensitive combination of tests (the Gold Standard) rather than the cheaper, automated ones that miss too many cases.
2. The "Time-Travel" Check: This is a crucial habit. Since Lyme antibodies can stay in your body for years, a single positive test doesn't tell you if you were infected today or ten years ago.
   • The Fix: Always compare your current blood test with your last year's blood test. If the "wanted posters" (antibodies) have suddenly multiplied or new ones appeared, that means you have a new infection that needs treatment. The study found that without this "time-travel" comparison, doctors often miss recent infections.

The Bottom Line

This paper is a wake-up call. It says that while we have good tools to find Lyme disease, we are using some of them incorrectly. By switching to more sensitive tests and always comparing new results with old ones, we can stop missing diagnoses, treat people faster, and prevent the long-term misery that comes from untreated Lyme disease.

In short: Don't trust just any metal detector. Use the best one, and always check if the signal is new or old.

Technical Summary

1. Problem Statement

Accurate diagnosis of Lyme disease (caused by Borrelia burgdorferi sensu lato) is critical for timely treatment and preventing long-term complications like arthritis or neuroborreliosis. However, the diagnosis relies heavily on serological testing, which faces significant challenges:

• Variable Sensitivity: Different commercial serological assays (ELISA and CLIA) exhibit varying levels of sensitivity, leading to inconsistent diagnostic outcomes.
• Missed Recent Infections: Serology cannot inherently distinguish between past cleared infections and recent active infections without longitudinal data.
• Clinical Consequences: Discrepancies between laboratories using different platforms can lead to false negatives, delayed treatment, and progression of the disease.
• High-Risk Populations: Occupational groups (forestry, agriculture, landscaping) have higher exposure rates, yet screening protocols vary widely in effectiveness.

2. Methodology

The study was conducted by Innatoss Laboratories (The Netherlands) using a retrospective cohort design.

• Study Population:
  • Cohort: 60 positive serum samples from 57 individuals (aged 23–64) selected from an annual Lyme screening program targeting high-risk occupational groups (5,000+ participants).
  • Controls: Three clinically confirmed cases of Erythema Migrans (EM) were included to validate sensitivity in symptomatic cases.
  • Demographics: 50 males, 7 females; median age 51.
• Testing Protocols (Two-Tier Algorithm):
  • Reference Protocol (Tier 1): EUROIMMUN Anti-Borrelia (IgG/IgM) ELISA + ZEUS VlsE1/pepC10 (IgG/IgM) ELISA.
  • Comparator Protocols (Tier 1):
    • SERION Classic Borrelia burgdorferi (IgG/IgM) ELISA.
    • Diasorin LIAISON (IgG/IgM) Chemiluminescence Immunoassay (CLIA).
  • Confirmation (Tier 2): All positive Tier 1 results were confirmed using Viramed ViraStripe immunoblots (IgG/IgM).
• Longitudinal Analysis: Current results were compared against previous samples from the same individuals to identify seroconversions (new infections).
• Case Studies: Three specific cases with discrepant results between laboratories were investigated in depth.
• Statistical Analysis: Sensitivity was calculated for each protocol. Differences were assessed using McNemar's test with Bonferroni correction.

3. Key Contributions

• Quantification of Discrepancies: The study provides empirical data showing that the choice of serological assay significantly impacts diagnostic sensitivity in high-risk populations.
• Identification of "Missed" Infections: The research identified six specific cases of recent Borrelia infections that were missed by widely used alternative protocols (SERION and Diasorin) but detected by the EUROIMMUN/ZEUS protocol.
• Validation of Longitudinal Comparison: The study reinforces that comparing current results with historical patient data is essential for distinguishing recent infections from past exposure, a step often missed in single-timepoint testing.
• Clinical Case Evidence: The paper documents real-world clinical consequences, including a case where a patient with fatigue and joint pain was misdiagnosed due to a negative Diasorin result, only to be correctly diagnosed and treated after re-testing with a more sensitive protocol.

4. Results

• Sensitivity Comparison:
  • EUROIMMUN/ZEUS Protocol: Detected 96.8% of cases (95% CI: 89.1–99.1).
  • SERION Protocol: Detected 84.1% of cases (95% CI: 73.2–91.1). This was significantly lower than the reference (p = 0.023).
  • Diasorin CLIA Protocol: Detected 69.8% of cases (95% CI: 57.6–79.8). This was significantly lower than both the reference and SERION (p < 0.001).
• Missed Diagnoses:
  • The Diasorin CLIA missed 17 samples; the SERION ELISA missed 7 samples.
  • Six of these missed samples represented new infections (seroconversion confirmed by longitudinal data), meaning these patients would have been denied treatment if only the less sensitive tests were used.
  • One symptomatic control (C2) was missed by the SERION protocol but detected by the others.
• Specificity: All Tier 1 tests showed high and comparable specificity (90.2% – 98.0%) based on manufacturer data, indicating the issue is primarily one of sensitivity, not false positives.
• Immunoblot Discrepancies: Differences were also observed in Tier 2 immunoblots. For instance, in Case 3, the Viramed blot detected an OspC band (confirming infection) while the Mikrogen blot (used by the referring hospital) was negative.

5. Significance and Recommendations

• Clinical Impact: The use of less sensitive assays (particularly Diasorin CLIA, which is popular due to automation and cost) can lead to missed diagnoses, delayed antibiotic treatment, and increased risk of chronic Lyme complications.
• Standardization Needs: The authors call for a consensus panel to define minimum performance criteria for Borrelia serological assays.
• Protocol Optimization:
  • Adoption of broader two-tier protocols (e.g., combining EUROIMMUN and ZEUS) is recommended for higher sensitivity.
  • Re-evaluation of immunoblot interpretation: A single positive VlsE band on an IgG blot should not be dismissed as equivocal/negative, as it may indicate early infection.
• Systemic Improvements:
  • Longitudinal Data Integration: Electronic health records should be integrated with laboratory systems to automatically flag and compare current results with historical data for high-risk individuals.
  • International Standards: Development of an international standard containing relevant antigens to allow for precise quantification of antibodies across different platforms.

Conclusion: The study demonstrates that significant variability exists between widely used Lyme serological tests. To prevent missed diagnoses and improve patient outcomes, the authors advocate for the adoption of more sensitive testing strategies, harmonized interpretation guidelines, and the routine comparison of longitudinal patient data.