INFECTIOUS SEROLOGY – BACTERIOLOGY – BORRELIA | ANAPLASMA

Key Points

• Lyme disease and anaplasmosis are tick-borne infections with potentially serious long-term effects if not treated promptly.
• Two-level testing uses ELISA screening followed by immunoblot confirmation to reduce false positives.
• Test sensitivity for Lyme disease is only 20–50% in early localized infection, so repeat testing after 2–3 weeks may be needed.
• For suspected neuroborreliosis, cerebrospinal fluid testing with Antibody Index calculation can confirm intrathecal antibody production.
• Tests using recombinant antigens offer higher diagnostic confidence, with several assays showing sensitivity and specificity above 95%.

• Background: Two Tick-Borne Illnesses
• The Phases of Lyme Borreliosis
• Human Granulocytic Anaplasmosis (HGA)
• How Doctors Diagnose These Infections
• Test Sensitivity Across Disease Stages
• The Science Behind the Tests: Key Antigens
• ELISA Testing Explained
• Immunoblot (Western Blot) Testing Explained
• Automated Testing with BlueBLOT-LINE
• Microblot-Array: Advanced Multiplex Technology
• Neuroborreliosis and the Antibody Index
• Clinical Implications for Patients
• Limitations and Important Considerations
• Recommendations for Patients
• Source Information

Background: Two Tick-Borne Illnesses

Lyme borreliosis (commonly called Lyme disease) is a multi-system infectious disease caused by spiral-shaped bacteria called Borrelia burgdorferi (a type of spirochete). The infection is transmitted to humans through the bite of ticks belonging to the Ixodes genus—the same deer ticks that are common in many parts of the world.

Lyme disease is characterized by both early and late clinical symptoms that can affect virtually any system in the body. Human granulocytic anaplasmosis (HGA) is a separate illness caused by a different bacterium called Anaplasma phagocytophilum. In many regions, the castor bean tick, Ixodes ricinus, serves as the vector for both diseases. While the tick is sucking blood, the bacteria enter the host's cardiovascular system, where they attack blood cells.

These infections matter to patients because they are often missed or misdiagnosed. The symptoms can mimic many other conditions, and antibody testing is not always straightforward. Understanding how the tests work can help you ask the right questions if you or a loved one is being evaluated for a tick-borne illness.

The Phases of Lyme Borreliosis

Lyme disease progresses through three distinct phases, each with its own set of symptoms and diagnostic challenges.

Early Localized Infection (Days to Weeks)

This first phase is characterized by erythema migrans (EM), the classic "bull's-eye" rash. Importantly, this rash appears in only 50% of patients. Early symptoms may also include "flu-like" symptoms, headache, and swollen lymph nodes (lymphadenitis). This means half of all infected patients may not have the tell-tale rash that most people associate with Lyme disease.

Early Disseminated Infection (Weeks to Months)

During this phase, Borrelia bacteria spread through blood vessels and the lymphatic system to reach the central nervous system (CNS), joints, heart, eyes, skin, and other organs. The most frequently diagnosed symptoms at this stage include:

• Neuroborreliosis—infection of the nervous system
• Paresis neurofacialis—facial nerve paralysis (Bell's palsy)
• Borrelial lymphocytoma—bluish-red swellings, often on the earlobes or knuckles
• Bannwarth syndrome—a combination of nerve pain, meningitis, and facial palsy

Additional symptoms can include skin changes (in about 20% of cases) and non-specific symptoms that resemble many other illnesses: swollen glands, headaches, muscle pains, nausea, vomiting, abdominal problems, and frequent pareses (muscle weakness or partial paralysis).

Late Disseminated Infection (Months to Years)

Without effective treatment, the disease can progress to a late phase lasting months or even years. The most typical immune-related changes diagnosed at this stage are:

• Acrodermatitis chronica atrophicans (ACA)—chronic skin lesions that can cause skin thinning and discoloration
• Chronic neuroborreliosis—ongoing nervous system involvement
• Borrelial arthritis—inflammation of the joints, often the knees

Extensive studies have shown that different Borrelia genospecies (subtypes) are associated with different clinical presentations. B. garinii is associated with neurological symptoms, B. afzelii with chronic skin disorders (especially ACA), and B. burgdorferi sensu stricto is mainly related to joint injuries. All genospecies can, however, cause erythema migrans and many other clinical manifestations.

Human Granulocytic Anaplasmosis (HGA)

Anaplasmosis is an acute illness that typically develops within one week after a tick bite. The symptoms can range from completely asymptomatic forms to serious, life-threatening conditions involving respiratory, gastrointestinal, renal, and neurological symptoms.

The first and most common sign is a feverish state lasting at least 3 to 7 days following a tick bite. Serious complications are more likely in patients with weakened immune systems (immunodeficit), individuals who have undergone transplantation, and patients without a spleen. The disease is usually acute; however, more complicated cases that are not treated in time can become chronic and might even be life-threatening.

One notable epidemiological finding is that men are four times more likely than women (4:1) to become ill with anaplasmosis.

Diagnosing HGA based only on clinical symptoms is very difficult, which is why laboratory findings are essential. Characteristic laboratory findings include:

• Leukopenia—low white blood cell count
• Thrombocytopenia—low platelet count
• Elevated liver transaminases—signs of liver involvement on blood tests

Antibody production begins within the first 2 weeks after disease onset. However, only 30–60% of patients test positive (seropositive) during the acute phase. This number rises to 70–90% during convalescence (the recovery period), which has important implications for when testing should occur.

How Doctors Diagnose These Infections

The diagnosis of Lyme disease and anaplasmosis is based on three elements: the patient's medical history (anamnesis), the clinical picture (symptoms and physical findings), and the results of laboratory tests. Currently, the diagnostic methods of choice are screening for specific IgG and IgM antibodies using ELISA, followed by confirmation of antibodies to specific antigens using immunoblot. Direct cultivation of the bacteria or electron microscopy is not practical for routine use.

Serological diagnosis of borreliosis is challenging for several reasons:

• The large genetic diversity of the species Borrelia burgdorferi sensu lato
• Possible cross-reactivity with unrelated antigens from other microorganisms
• Borrelia's richness in heat shock proteins, which can trigger non-specific immune responses
• Highly variable individual serological reactivity
• Extremely slow antibody production in the early phase of the disease
• IgG and IgM antibodies can persist for more than ten years, making it hard to distinguish past from active infection

The Two-Level Testing Approach

To maximize accuracy, doctors use a two-level antibody detection strategy. This approach is endorsed by European and American guidelines (as summarized by Eldin et al., 2019).

1. Level 1 (Screening): Samples are tested with the ELISA method, which divides patients into positive or negative groups based on their antibody status.
2. Level 2 (Confirmation): Positive and borderline results are confirmed using immunoblot, which detects antibodies against specific Borrelia antigens.

If the first test is negative but the patient's symptoms persist, a second (control) blood sample should be collected 2–3 weeks later and re-tested. This is important because antibody levels can be undetectable in the earliest stages of infection.

The number of disagreements between immunoblot (level 2) and ELISA (level 1) results is reduced when the ELISA method is based on recombinant antigens, as is the case with the TestLine assays described in this article.

A test result alone does not make the diagnosis—it supports it. The final diagnosis is based on the comprehensive clinical picture of the patient, not only on the serological result.

Test Sensitivity Across Disease Stages

One of the most important facts for patients to understand is that the sensitivity of these tests—their ability to detect the disease when it is present—varies dramatically depending on the stage of the illness. According to the German MiQ quality standards, the diagnostic sensitivity for different forms of Lyme borreliosis is:

• Localized early infection (erythema migrans, borrelial lymphocytoma, multiple EM): 20–50%
• Disseminated early infection (neuroborreliosis, Lyme arthritis, carditis): 70–90%
• Disseminated late infection (acrodermatitis chronica atrophicans, late neuroborreliosis): 90–100%

In other words, a negative test result early in the disease does not rule out Lyme disease. This is why repeat testing after 2–3 weeks is so important when symptoms persist.

The Science Behind the Tests: Key Antigens

Modern diagnostic tests do not just look for any antibody—they look for antibodies against specific proteins (antigens) of the bacteria. Each antigen appears at different times during infection and is associated with different clinical manifestations. Here are the key Borrelia antigens used in these tests:

• VlsE (Ba, Bg, Bs)—the main antigen of the early and late antibody response. It significantly increases test sensitivity; approximately 90% of positive sera and cerebrospinal fluid samples react to this antigen band.
• p83—the main extracellular protein, a late antibody response antigen highly typical of neuroborreliosis.
• p58 (OppA-2)—a membrane transporter considered a marker of the disseminated stage of Lyme disease.
• p41 (Ba, Bs)—the inner part of flagellin, a highly specific antigen of the early antibody response.
• p39 (BmpA)—a glycosaminopeptide receptor and an antigen of the late response. It is significant for advanced disseminated Lyme disease and is often associated with Lyme arthritis.
• OspA (Ba, Bg, Bs)—outer surface protein A, a late response antigen typical for neuroborreliosis.
• OspB—outer surface protein B, a late response antigen.
• OspC (Ba, Bg, Bs, Bsp)—outer surface protein C, the immunodominant marker of the IgM antibody response (the earliest antibodies produced).
• OspE—outer surface protein E.
• NapA—neutrophil activating protein A, a strong immunogen and a main marker of Lyme arthritis pathogenesis.
• p17 (DbpA)—decorin-binding protein A, involved in both early and late antibody responses and typical of neuroborreliosis.

The letters Ba, Bg, Bs, and Bsp refer to the specific bacterial subspecies the antigen comes from: B. afzelii, B. garinii, B. burgdorferi sensu stricto, and B. spielmanii.

Anaplasma and Cross-Reacting Antigens

For anaplasmosis, the key antigens are p44 (the main antigen of the antibody response to HGA), OmpA (an outer membrane protein and significant virulence marker), and Asp62 (a membrane transporter surface protein).

Tests also include antigens to detect cross-reactions with other infections: TpN17, a highly specific membrane protein of Treponema pallidum (the bacterium that causes syphilis), and VCA-p18, a viral capsid antigen that detects EBV (Epstein-Barr virus) infection. Including these antigens helps prevent false-positive results caused by antibodies to unrelated infections.

ELISA Testing Explained

ELISA (Enzyme-Linked Immunosorbent Assay) is the first-level screening test. The TestLine EIA assays are based on a sandwich-type ELISA method. They are designed for the detection of IgG and IgM antibodies in human serum, plasma, cerebrospinal fluid, or synovial (joint) fluid.

Patient-Friendly Protocol Overview

The testing process is straightforward and takes about 1.5 hours total:

1. Samples are diluted: serum/plasma at 1:101 (10 μl + 1 ml), cerebrospinal fluid at 1:2 (110 μl + 110 μl), or synovial fluid at 1:21 or 1:41.
2. Controls and diluted samples are pipetted into the microplate wells (100 μl each).
3. The plate is incubated for 30 minutes at 37°C.
4. Wells are aspirated and washed 4 times.
5. Conjugate (the detection antibody) is added (100 μl), followed by another 30-minute incubation at 37°C.
6. Wells are washed 5 times.
7. Substrate solution (TMB-Complete) is added (100 μl) and incubated for 15 minutes at 37°C.
8. Stopping solution is added, and the color intensity is read at 450 nm.

Results are evaluated semiquantitatively using an Index of Positivity (IP), which compares the patient sample to the included cut-off control. The kits come with ready-to-use, color-coded components and breakable microplate strips, making them convenient for laboratories.

ELISA Performance: What the Numbers Mean

The diagnostic performance of these tests is remarkably high. For patients, this means you can trust a confirmed result. The key metrics are sensitivity (the ability to correctly identify those with the disease) and specificity (the ability to correctly identify those without the disease):

• EIA Borrelia recombinant IgG: 98.3% sensitivity, 98.1% specificity
• EIA Borrelia recombinant IgM: 99.1% sensitivity, 97.3% specificity
• EIA Borrelia afzelii VlsE IgG: 98.9% sensitivity, 98.9% specificity
• EIA Borrelia afzelii IgM: 95.6% sensitivity, 99.0% specificity
• EIA Borrelia b. sensu stricto VlsE IgG: 98.9% sensitivity, 98.9% specificity
• EIA Borrelia b. sensu stricto IgM: 97.5% sensitivity, 98.9% specificity
• EIA Borrelia garinii VlsE IgG: 98.9% sensitivity, 99.0% specificity
• EIA Borrelia garinii IgM: 95.7% sensitivity, 98.9% specificity

These kits use recombinant (genetically engineered) antigens from specific Borrelia species, including VlsE (Ba, Bg, Bs), p83, p58, p41 (internal flagellin), p39, OspA, OspB, OspC, OspE, p17, and NapA. Whole-cell antigen versions are also available, enriched with VlsE, for each major genospecies.

Why Recombinant Antigens Matter: The Antibody Response Study

Research shows that recombinant antigen tests detect the antibody response with higher dynamics (meaning they show clearer positive results) than tests using whole-cell antigens. In a study of 86 patients with Lyme neuroborreliosis, the Index of Positivity was consistently higher with recombinant antigen ELISAs (both IgG and IgM) compared to whole-cell antigen ELISAs. This translates to fewer borderline results and greater diagnostic confidence.

Immunoblot (Western Blot) Testing Explained

Immunoblot—commonly known as Western blot—is the second-level confirmation test. It works by separating specific bacterial proteins and fixing them onto a nitrocellulose membrane strip. If the patient's blood contains antibodies against these proteins, they bind to the strip and produce visible colored bands, rather like a barcode. This tells doctors exactly which bacterial proteins the immune system is reacting to.

What a Patient Should Know About the Procedure

1. Samples are diluted: serum/plasma at 1:51 (30 μl + 1.5 ml), cerebrospinal fluid at 1:2, or synovial fluid at 1:17.5.
2. Strips are soaked in a universal solution for 10 minutes.
3. Diluted samples are added and incubated for 30 minutes on a shaker.
4. Strips are washed 3 times for 5 minutes.
5. Conjugate is added and incubated for 30 minutes.
6. Strips are washed again, then substrate solution (BCIP/NBT) is added for 15 minutes.
7. After a final wash, strips are dried and evaluated.

Each strip includes a control line to verify the test worked properly. The advantages of immunoblot testing include easy interpretation, high reproducibility, and the ability to detect antibodies in cerebrospinal fluid. The BLOT-LINE series includes separate kits for B. afzelii, B. garinii, B. burgdorferi sensu stricto, combined Borrelia/HGA, and standalone Anaplasma IgG and IgM testing.

Immunoblot Performance Data

• BLOT-LINE Anaplasma IgG: 92.0% sensitivity, 94.0% specificity
• BLOT-LINE Anaplasma IgM: 91.4% sensitivity, 99.0% specificity
• BLOT-LINE Borrelia/HGA IgG: 96.8% sensitivity, 98.5% specificity (for Borrelia); 92.9% sensitivity, 96.3% specificity (for Anaplasma)
• BLOT-LINE Borrelia/HGA IgM: 97.1% sensitivity, 96.4% specificity (for Borrelia); 94.7% sensitivity, 97.1% specificity (for Anaplasma)
• BLOT-LINE Borrelia afzelii IgG: 97.3% sensitivity, 96.9% specificity
• BLOT-LINE Borrelia afzelii IgM: 96.6% sensitivity, 95.9% specificity
• BLOT-LINE Borrelia garinii IgG: 97.1% sensitivity, 96.2% specificity
• BLOT-LINE Borrelia garinii IgM: 95.2% sensitivity, 97.0% specificity
• BLOT-LINE Borrelia b. sensu stricto IgG: 96.8% sensitivity, 96.9% specificity
• BLOT-LINE Borrelia b. sensu stricto IgM: 96.2% sensitivity, 96.8% specificity

Which Borrelia Species Test Is Best for Neuroborreliosis?

A study of 60 patients with neuroborreliosis compared the reactivity of the three species-specific BLOT-LINE kits. The BLOT-LINE Borrelia garinii kit showed more than 20% higher reactivity in this patient group compared to the B. afzelii and B. burgdorferi sensu stricto kits, for both IgM and IgG. This makes sense because B. garinii is the species most commonly associated with neurological symptoms. In a separate study of 87 patients with neuroborreliosis, antibodies against VlsE (a key diagnostic antigen) were found in approximately 80% of serum samples and 70% of CSF samples. In patients where neuroborreliosis was excluded, and in healthy controls (n=68), these rates were substantially lower. If you have neurological symptoms, your doctor may specifically order the B. garinii immunoblot because of its higher sensitivity for this form of the disease.

Automated Testing with BlueBLOT-LINE

For high-volume laboratories, the BlueDiver Instrument combined with BlueBLOT-LINE Borrelia kits offers a fully automated solution. This system automatically handles batch and expiry control via barcode reading, pipetting, incubation, and washing—reducing the risk of human error.

The total assay time is 1 hour and 14 minutes: incubation with the sample for 30 minutes, 20 minutes with conjugate, and 10 minutes with substrate, with automated washing steps in between.

The BlueBLOT-LINE strips include reactive control lines and separate conjugate controls for IgG and IgM, plus a wide array of antigens: VlsE (Ba, Bg, Bs), p83, p58, p41, p39, OspB, OspA, OspC, p17, NapA, p44, OmpA, TpN17, and EBV p18. Performance data show:

• BlueBLOT-LINE Borrelia IgG: 97.4% sensitivity, 99.0% specificity (for Borrelia); 83.0% sensitivity, 99.0% specificity (for Anaplasma)
• BlueBLOT-LINE Borrelia IgM: 98.3% sensitivity, 99.0% specificity (for Borrelia); 92.0% sensitivity, 96.0% specificity (for Anaplasma)

Microblot-Array: Advanced Multiplex Technology

The Microblot-Array represents the newest generation of confirmation testing. Specific recombinant proteins are applied as tiny spots to a nitrocellulose membrane that fits into a standard microtitre plate well. This clever design means the test can be processed using standard ELISA laboratory equipment, while simultaneously testing for multiple infections at once (multiplex technology).

One key patient benefit is low sample consumption—only tiny amounts of blood or fluid are needed. The antigens are spotted in triplicate to minimize statistical variation, and each well includes reference spots, test controls, conjugate controls (separate for IgG and IgM), and four calibration spots to ensure validity.

Microblot-Array Performance Data

This test was validated on human serum samples with the following results:

• Borrelia IgG: 98.7% sensitivity (n=74), 98.9% specificity (n=100)
• Borrelia IgM: 98.5% sensitivity (n=56), 99.9% specificity (n=95)
• Anaplasma IgG: 92.0% sensitivity (n=25), 99.9% specificity (n=30)
• Anaplasma IgM: 95.0% sensitivity (n=20), 99.9% specificity (n=38)
• Treponema IgG: 98.3% sensitivity (n=59), 99.9% specificity (n=30)
• EBV IgM: 99.9% sensitivity (n=39), 99.9% specificity (n=51)

Comparative studies showed that the Microblot-Array agrees with conventional ELISA results 92.2% of the time for IgG and 90.7% for IgM. When compared specifically to recombinant antigen ELISA and Western blot methods, agreement was 92% and 90%, respectively. The small percentage of disagreements (8–10%) highlights why clinical correlation is essential—no test is perfect, and a doctor's judgment matters.

Neuroborreliosis and the Antibody Index

For patients with suspected nervous system involvement (neuroborreliosis), a special calculation called the Antibody Index (AI) is crucial. According to the international recommendation of the European Union Concerted Action on Lyme Borreliosis (EUCALB), evidence of intrathecal antibody production is necessary for the diagnosis of early and late neuroborreliosis. In plain language, this means doctors must prove that antibodies are being produced inside the spinal fluid, not just that they are present in the blood.

The antibody level in cerebrospinal fluid (CSF) depends on three factors:

• Antibodies present in blood serum (which can leak into the CSF)
• The permeability of the blood-CSF barrier
• Actual intrathecal (inside the spinal fluid) production of antibodies

The presence of specific antibodies alone—whether in serum or CSF—is not sufficient evidence of neuroborreliosis. The AI calculation compares the ratio of specific antibodies in the CSF and serum relative to the state of the blood-CSF barrier and total immunoglobulin levels. This test can be done with a small CSF sample of approximately 0.15 ml, and dedicated Antibody Index Software handles the calculations automatically.

The interpretation table is straightforward:

• Serum negative, CSF positive: Intrathecal synthesis confirmed—positivity verified (EUCALB recommendation).
• Serum positive, CSF positive: Usually positive, but passive transfer of antibodies through a disturbed blood-CSF barrier is possible—AI determination is needed.
• Serum positive, CSF negative: Possibly positive, provided the measured absorbance values in the CSF and serum are close to the cut-off control—AI determination is needed.
• Serum negative, CSF negative: Negative.

The accuracy of AI calculations is regularly verified through participation in external quality assessment programs involving over 200 laboratories, organized by the independent scientific society Instand e.V. TestLine's AI results have consistently performed well in these programs.

Clinical Implications for Patients

What does all this technical information mean for you as a patient? Several practical implications follow from the data:

First, timing matters. If you were bitten by a tick and develop symptoms, testing too early can produce a false negative. The sensitivity of ELISA testing for early localized Lyme disease is only 20–50%. If your test is negative but symptoms persist, a repeat test in 2–3 weeks is essential. Similarly, anaplasmosis antibodies are only detectable in 30–60% of patients during the acute phase, rising to 70–90% during recovery.

Second, the two-level testing strategy protects you. The combination of ELISA screening followed by immunoblot confirmation dramatically reduces false positives. Tests with specificity above 97% mean that fewer than 3 out of 100 healthy people will be incorrectly identified as infected—and confirmation testing catches most of those.

Third, the type of test matters. Tests using recombinant antigens (genetically engineered specific proteins) show higher dynamics of antibody response than whole-cell antigen tests. This means they produce clearer positive/negative results with fewer ambiguous borderline readings, especially in patients with neuroborreliosis. If you have neurological symptoms, a B. garinii-specific test may be significantly more informative—it showed more than 20% higher reactivity in neuroborreliosis patients compared to tests for other Borrelia species.

Fourth, CSF testing adds value for neurological symptoms. If your doctor suspects the infection has reached your nervous system, testing both blood and cerebrospinal fluid, and calculating the Antibody Index, can provide definitive evidence—beyond a doubt—of active neuroborreliosis.

Limitations and Important Considerations

No diagnostic test is perfect, and it is important to understand the limitations of serological testing for tick-borne diseases:

• False negatives early in the disease: The immune system takes time to produce detectable antibodies. In early Lyme disease, sensitivity can be as low as 20–50%.
• Antibody persistence: IgG and IgM antibodies can persist for more than ten years after infection. A positive test does not necessarily mean you have an active infection requiring treatment—it could reflect a past infection.
• Cross-reactivity: Antibodies to other organisms (such as Treponema pallidum, the syphilis bacterium, or EBV) can sometimes cause false positives. This is why tests include specific antigens to detect and exclude these cross-reactions.
• Individual variation: Different people produce antibodies at different rates and intensities. Some patients may have borderline results that require repeat testing.
• The test supports, but does not make, the diagnosis: The clinical picture—your symptoms, physical examination, and exposure history—is always the foundation of the diagnosis. Serological results must be interpreted in this context.
• Serious complications in vulnerable patients: Patients with weakened immune systems, transplant recipients, and those without a spleen are at higher risk for severe anaplasmosis and should seek medical attention promptly after a tick bite.

Recommendations for Patients

If you are concerned about Lyme disease or anaplasmosis, here are practical, evidence-based recommendations:

1. See a doctor promptly if you develop a fever, rash, headache, muscle pain, or neurological symptoms within weeks after a known tick bite. Do not wait for symptoms to resolve on their own.
2. Know that the classic bull's-eye rash appears in only half of Lyme patients. The absence of a rash does not rule out the disease.
3. If your first test is negative but symptoms persist, ask about repeat testing in 2–3 weeks. A single early negative test is not definitive.
4. Request the two-level testing approach: ELISA screening with immunoblot confirmation for positive or borderline results. This is the international standard of care.
5. If you have neurological symptoms (facial palsy, numbness, tingling, memory problems, persistent headache), ask your doctor whether cerebrospinal fluid testing with Antibody Index calculation is appropriate.
6. Be aware of the species-specific issue: If neuroborreliosis is suspected, a B. garinii-specific test may be more sensitive.
7. Provide a complete history: Tell your doctor about any tick exposures, travel, outdoor activities, and all symptoms, even vague ones. The clinical picture is essential to correct interpretation of test results.
8. Do not self-diagnose or self-treat. Antibiotic treatment decisions should be made by a healthcare professional based on the full clinical picture and confirmed laboratory results.

Frequently Asked Questions

What is the two-level testing strategy for Lyme disease and why is it used?

Doctors first screen your blood with an ELISA test. If that result is positive or borderline, a second confirmation test called an immunoblot is done. This two-level approach is recommended by European and American guidelines. It reduces false positives and gives more accurate results, so you can trust a confirmed result.

My Lyme disease test was negative, but I still have symptoms. What should I do?

If your first test is negative but symptoms persist, ask your doctor about a repeat blood test in 2 to 3 weeks. Antibodies take time to develop, and early sensitivity can be as low as 20–50%. A single early negative test does not rule out Lyme disease.

Why might my doctor order a cerebrospinal fluid (CSF) test for neurological symptoms?

If your doctor suspects neuroborreliosis, testing CSF can check for antibody production inside the spinal fluid. A special calculation called the Antibody Index (AI) helps prove whether antibodies are made locally. This can give definitive evidence of active nervous system infection, even if blood tests are unclear.

What are the key differences between Lyme disease and anaplasmosis?

Lyme disease is caused by Borrelia bacteria and can cause rash, joint pain, and neurological problems. Anaplasmosis is caused by Anaplasma bacteria and usually starts with fever within a week after a tick bite. Both are spread by the same ticks and can be serious if not treated. Laboratory tests help tell them apart.

How accurate are modern tests for Lyme disease?

Modern ELISA tests have sensitivity and specificity over 95% for most Lyme-specific tests. For example, the Borrelia recombinant IgG test has 98.3% sensitivity and 98.1% specificity. Immunoblot tests also show high accuracy, with sensitivity around 96–98% for Borrelia. However, early infection can still be missed, so timing matters.

What does a positive Lyme disease test mean if I was infected years ago?

Antibodies can persist for more than ten years after infection. A positive test does not necessarily mean you have an active infection requiring treatment. Your doctor will interpret the result along with your symptoms, physical exam, and exposure history to decide if treatment is needed.

My Lyme disease test was negative but I still have symptoms. Should I get a second opinion?

Yes, a second opinion can be valuable if your Lyme disease test is negative but symptoms persist. Early Lyme disease tests have only 20–50% sensitivity, so a negative result does not rule out infection. Repeat testing after 2–3 weeks is often needed. A second opinion can help ensure appropriate testing, such as immunoblot confirmation or cerebrospinal fluid analysis for neurological symptoms. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original Article Title: INFECTIOUS SEROLOGY – BACTERIOLOGY – BORRELIA | ANAPLASMA

Content Source: This article is based on technical documentation from TestLine Clinical Diagnostics regarding their ELISA, Immunoblot, and Microblot-Array diagnostic kits for Borrelia burgdorferi and Anaplasma phagocytophilum. Data presented include the manufacturer's validation studies, external quality assessment results (Instand e.V., May 2021, over 200 participating laboratories), and a comparative study of 86 patients with Lyme neuroborreliosis and 60 patients in a species-reactivity study (data prepared for publication).

Guideline Reference: The two-level antibody detection strategy is based on: Eldin C, Raffetin A, Bouiller K, et al. Review of European and American guidelines for the diagnosis of Lyme borreliosis. Médecine et Maladies Infectieuses. 2019;49(2):121-132. doi:10.1016/j.medmal.2018.11.011

Note: This patient-friendly article is based on peer-reviewed research and manufacturer validation data. It is provided for educational purposes and does not replace professional medical advice. Always consult a qualified healthcare provider for diagnosis and treatment decisions.