The IgM Babesia test measures early antibodies against Babesia species, tick-borne protozoan parasites that invade red blood cells and can cause babesiosis, a malaria-like illness. In North America, Babesia microti is most common, while B. divergens and B. venatorum predominate in Europe, often leading to more severe disease. IgM antibodies typically appear within 1–2 weeks of infection, making this marker useful for identifying recent or acute cases before IgG antibodies or confirmatory findings emerge. Clinically, babesiosis can range from flu-like symptoms (fever, chills, sweats, fatigue) to hemolytic anemia, splenomegaly, and multi-organ complications, especially in elderly or immunocompromised patients, or those without a spleen. Because the same ticks can also transmit Lyme disease (Borrelia) and Anaplasma, co-infections are common and can complicate the illness. 

An equivocal IgM Babesia result means antibody levels are near the cut-off, making the finding uncertain; this may reflect very early infection, low-level reactivity, or nonspecific response, and repeat or confirmatory testing is often needed for clarification.

The IgM Bartonella test detects early antibodies against Bartonella species, a group of bacteria transmitted by ticks, fleas, lice, or scratches from infected animals (especially cats). The most common human pathogens are Bartonella henselae and Bartonella quintana, which can cause cat scratch disease, trench fever, or tick-borne bartonellosis. In some cases, Bartonella infections may contribute to chronic fatigue, neurological issues, or joint pain, especially when co-infections with Lyme disease or Babesia are present.

The IgM Ehrlichia test detects early antibodies to Ehrlichia species, tick-borne bacteria that invade white blood cells and cause ehrlichiosis, most often due to E. chaffeensis (human monocytic ehrlichiosis) or E. ewingii. IgM antibodies usually appear within 1–2 weeks of illness, making this marker useful for identifying recent or acute infection, particularly in patients presenting with fever, severe headache, fatigue, muscle aches, gastrointestinal upset, or neurological changes. Laboratory findings commonly include low white blood cells, low platelets, and elevated liver enzymes. Because ehrlichiosis can progress rapidly to severe complications in older adults, immunocompromised patients, or those with delayed treatment, timely recognition and empiric doxycycline therapy are critical. However, IgM alone is not definitive since early levels can be low and false positives may occur. 

An equivocal IgM Ehrlichia result means the antibody level is near the cut-off, leaving the test uncertain; this may reflect very early infection, a nonspecific immune response, or cross-reactivity, and repeat or confirmatory testing (PCR or IgG serology) is often needed.

The IgM Immunodominant C6 test measures early antibodies against the conserved C6 peptide of VlsE, a key surface protein of Borrelia burgdorferi sensu lato. Because the IR6 region of VlsE is highly conserved across major Lyme-causing subspecies (B. burgdorferi sensu stricto, B. afzelii, B. garinii), C6-based assays serve as valuable pan-Borrelia markers in Lyme serology. IgM to C6 typically appears within 1–3 weeks of infection, making it especially useful for detecting recent exposure, particularly in patients with early localized symptoms, neurological manifestations, or evolving musculoskeletal involvement. While C6 ELISAs show strong sensitivity and specificity, IgM alone is not diagnostic—isolated IgM after 6–8 weeks or cross-reactivity with other pathogens (including Borrelia miyamotoi) can lead to nonspecific results. 

An equivocal IgM C6 result means antibody levels are near the cut-off, leaving interpretation uncertain; this may reflect very early infection, low-level reactivity, or a nonspecific immune response, so repeat or confirmatory testing is often required.

The IgM LFA Antigen + CK10 test measures two important parts of the immune system. The IgM portion looks for the body’s early-response antibodies, which usually appear soon after an infection begins, such as from a virus, bacteria, or parasite. Detecting IgM often suggests a recent or ongoing infection, while unusually persistent IgM levels may also point to chronic immune activity. The CK10 portion of the test checks for antibodies against cytokeratin 10, a protein found in skin and epithelial cells. Antibodies to CK10 can be a clue that the immune system is mistakenly targeting the body’s own tissues, as seen in certain autoimmune skin or inflammatory conditions. Together, these markers can help distinguish whether symptoms are more likely due to infection, autoimmunity, or both. 

If results are reported as equivocal, antibody levels are near the cut-off, meaning the test is uncertain; in these cases, repeat or confirmatory testing is often recommended.

IgM OspA + OspC

The IgM OspA + OspC test helps detect an early immune response to Borrelia burgdorferi, the bacteria that cause Lyme disease. It looks for IgM antibodies against two important surface proteins:

• OspC (Outer Surface Protein C): Typically produced within the first 2–3 weeks after infection, making it a strong marker for early Lyme disease.

• OspA (Outer Surface Protein A): More often linked with later or persistent infection, and sometimes associated with chronic or autoimmune-like Lyme symptoms.

By measuring IgM antibodies against both proteins, this test provides a broader view of where a person may be along the Lyme disease timeline.

Why It Matters

The IgM OspA + OspC test can be useful for people who have:

• Early Lyme symptoms such as rash, fever, fatigue, or muscle pain

• Neurological signs including facial palsy or nerve discomfort

• Joint pain or swelling that appears weeks to months after infection

• A history of tick exposure in areas where Lyme disease is common

Things to Keep in Mind

IgM antibodies are most reliable in the early weeks of infection. On their own, they cannot confirm Lyme disease. False positives are possible, which is why doctors often order additional testing (such as IgG antibodies, VlsE/C6 peptide, or multi-antigen panels) to confirm results.

Patient Takeaway

A positive IgM OspA + OspC test suggests that your immune system is reacting to Borrelia and may indicate a recent or active infection. However, your healthcare provider will always consider your symptoms, exposure history, and other test results before making a diagnosis.

If your result is reported as equivocal (borderline), it means the antibody level is close to the cutoff and not clearly positive or negative. In this case, repeat testing or confirmatory panels are often recommended to clarify the result.

The IgM OspE test detects early antibodies against Outer Surface Protein E (OspE) of Borrelia burgdorferi, the bacterium responsible for Lyme disease. OspE belongs to the Erp (OspE-related proteins) family, which helps Borrelia survive in the human bloodstream by binding to factor H, a host protein that protects the bacteria from complement-mediated killing.

The IgM Variable Major Protein E (VmpE) test detects early antibodies against a surface protein that Borrelia burgdorferi—the bacteria responsible for Lyme disease—uses to survive through antigenic variation. VmpE can repeatedly alter its structure, enabling Borrelia to evade immune detection and, in some cases, contribute to persistent or relapsing infection.

IgM antibodies to VmpE usually appear within the first 1–3 weeks after infection, making this test valuable for identifying recent exposure to Lyme disease. In some cases, IgM reactivity may also remain detectable in ongoing immune activation, offering insights into possible bacterial persistence.

Clinically, IgM VmpE provides complementary information to markers such as OspC and VlsE, helping clinicians assess both early immune recognition and potential long-term Borrelia activity.

As with all IgM-based assays, results must be interpreted alongside patient history, symptoms, and additional confirmatory markers.

An equivocal IgM VmpE result means antibody levels are near the test cut-off, leaving the finding uncertain. This may reflect very early infection, a nonspecific immune response, or cross-reactivity. In such cases, repeat or follow-up testing is usually recommended to clarify the result.

IL-1 beta refers to Interleukin-1 beta. Interleukin-1 beta is one of the cytokines assessed in the CytoDx Cytokine Response Profile offered by Diagnostic Solutions Laboratory. Cytokines are critical mediators of immune responses, and their imbalances have been linked to chronic inflammation and autoimmune diseases.

IL-10 (Interleukin-10) is a powerful anti-inflammatory cytokine that helps control immune overactivation and maintain immune tolerance. Produced by regulatory T cells (Tregs), monocytes, and macrophages, IL-10 suppresses excessive inflammatory signals and supports healing once an immune threat is cleared. Elevated IL-10 levels may indicate the body’s effort to calm chronic inflammation or infection, while low IL-10 often reflects poor immune regulation and a higher risk of autoimmune or inflammatory disorders. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-10 serves as a key marker of regulatory immune balance, helping clinicians assess whether inflammation is being effectively resolved or remains persistently active.

IL-13 (Interleukin-13) is an anti-inflammatory Th2 cytokine that regulates antibody production, tissue repair, and mucosal immunity. Produced by Th2 cells, mast cells, and ILC2s, IL-13 helps resolve inflammation but can also drive allergic and fibrotic responses when elevated. High IL-13 levels are linked to asthma, eczema, allergic rhinitis, and fibrotic diseases, indicating Th2 immune dominance. Low IL-13 may occur in autoimmune or Th1/Th17-driven inflammation, reflecting reduced regulatory control. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-13 serves as a marker of anti-inflammatory activity and immune balance, helping clinicians determine whether the immune system is effectively resolving inflammation or skewed toward chronic allergic or inflammatory stress.

IL-15 (Interleukin-15) is a pro-inflammatory cytokine that activates natural killer (NK) cells and CD8+ T cells, strengthening the body’s defense against infections and tumors. It also promotes interferon-gamma (IFN-γ) production, amplifying immune responses. Elevated IL-15 levels can indicate chronic inflammation, autoimmune activity, or persistent infection, and are often seen in conditions like rheumatoid arthritis, celiac disease, and inflammatory bowel disease. Low IL-15 may suggest reduced immune cell function or immune suppression. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-15 serves as a marker of Th1-driven immune activation, offering valuable insight into immune system stress and helping guide targeted approaches to restore immune balance and resilience.

IL-17A (Interleukin-17A) is a pro-inflammatory cytokine produced by Th17 cells that plays a key role in defending against bacterial and fungal infections. It promotes neutrophil recruitment and stimulates other inflammatory cytokines like IL-6 and TNF-α. Elevated IL-17A levels indicate Th17-dominant inflammation and are commonly seen in autoimmune diseases, psoriasis, IBD, and chronic inflammatory conditions. Chronically high IL-17A can drive tissue damage and immune dysregulation, while low IL-17A may signal weakened mucosal immunity or immune suppression. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-17A helps identify chronic inflammatory patterns and autoimmune activity, offering valuable guidance for restoring immune balance and reducing inflammation.

IL-18 (Interleukin-18) is a pro-inflammatory cytokine that activates Th1 and natural killer (NK) cells, driving the release of interferon-gamma (IFN-γ) and amplifying immune and inflammatory responses. While essential for fighting infections, persistently high IL-18 levels can promote chronic inflammation, autoimmune reactions, metabolic stress, and cardiovascular or neuroinflammatory disorders. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-18 serves as a key marker of Th1/Th17 pathway activity, helping identify immune system overactivation or imbalance. Elevated IL-18 often reflects ongoing inflammatory stress, whereas balanced levels indicate healthy immune communication and regulation.

IL-2 (Interleukin-2) is a pro-inflammatory Th1 cytokine that promotes the growth and activation of T cells, NK cells, and B cells, playing a key role in immune defense and regulation. Produced by activated T-helper cells, IL-2 strengthens immune responses while also supporting regulatory T cells (Tregs) to prevent autoimmunity. Elevated IL-2 levels often indicate immune activation, autoimmune activity, or chronic inflammation, whereas low IL-2 may reflect immune exhaustion, poor T-cell function, or regulatory imbalance. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-2 serves as a core marker of Th1 immune strength and balance, helping clinicians evaluate whether the immune system is properly activated, overactive, or suppressed.

IL-4 (Interleukin-4) is an anti-inflammatory cytokine that promotes Th2 immune activity and supports antibody production, immune tolerance, and tissue repair. Produced by Th2 cells, mast cells, and basophils, IL-4 helps suppress excessive Th1-driven inflammation. Elevated IL-4 levels are often linked to allergies, asthma, eczema, and parasitic infections, reflecting Th2 dominance and increased antibody activity. Low IL-4 may occur in autoimmune or chronic inflammatory states, where regulatory immune signaling is reduced. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-4 serves as a key marker of anti-inflammatory balance, helping clinicians determine whether a patient’s immune system is tilted toward inflammatory (Th1/Th17) or regulatory (Th2) pathways.

IL-5 (Interleukin-5) is an anti-inflammatory Th2 cytokine that stimulates the production and activation of eosinophils, immune cells involved in allergic reactions, asthma, and defense against parasites. Produced by Th2 cells, mast cells, and ILC2s, IL-5 promotes antibody production and supports mucosal immunity. Elevated IL-5 levels are often seen in allergic diseases, asthma, and eosinophilic inflammation, indicating a Th2-dominant immune response. Low IL-5 may occur in Th1/Th17-driven inflammation or immune suppression, leading to reduced mucosal protection. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-5 serves as a marker of anti-inflammatory and Th2 activity, helping clinicians evaluate whether the immune system is balanced or skewed toward chronic inflammation or allergic hypersensitivity.

IL-6 (Interleukin-6) is a pro-inflammatory cytokine that plays a central role in inflammation, immune defense, and metabolic regulation. Produced by immune and tissue cells, IL-6 triggers the liver’s acute-phase response, supports antibody production, and influences energy metabolism. Elevated IL-6 levels indicate chronic inflammation and are associated with autoimmune disease, metabolic dysfunction, cardiovascular disease, and chronic infection. Persistently high IL-6 can also promote fatigue, tissue damage, and oxidative stress. Low IL-6 may reflect suppressed immune function or reduced inflammatory capacity. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-6 serves as a key marker of systemic inflammation and immune activation, helping clinicians identify chronic inflammatory drivers and guide strategies to restore immune balance.

IL-7 (Interleukin-7) is a cytokine essential for the development, maintenance, and survival of T and B lymphocytes, key players in the body’s adaptive immune system. Produced by stromal and epithelial cells in the bone marrow and thymus, IL-7 helps sustain immune cell balance and readiness. Elevated IL-7 levels often reflect immune activation, lymphocyte depletion, or chronic inflammation, as the body increases IL-7 production to replenish immune cells. High IL-7 can be seen in autoimmune diseases, chronic viral infections, and metabolic or inflammatory disorders, while low levels may indicate immune suppression or impaired bone marrow function. Within the Cytokine Response Profile (CytoDx) by Diagnostic Solutions Laboratory, IL-7 serves as a key marker of immune activity and adaptive resilience, helping clinicians assess whether the immune system is in a state of activation, recovery, or dysregulation.